I told my sister she cannot live with me anymore.

Oof, there is so much to this situation and I will try to be as brief and thorough as possible. My sister (19) is 10 years younger than me and has a history of getting into really shit relationships with guys going back to age 15. When she was 16, I found out she was secretly dating someone well into his 20s and also found out that he had felony charges relating to his unsolicited involvement with minors in the past. Back then, I confronted her about this and told her how dangerous this person was, and she completely lost it with me, made excuses for him, etc. Due to her lack of maturity and immediately taking his side, I immediately called our parents and told them what I found out. She continued to date this person until she was about 18 and a half (trust me I know, our parents should have done a better job to stop this, but there wasn't much I could do being her sister). Her lifelong dream since she was a little girl was to live with me. We have been incredibly close her entire life, up until the issues with this guy, when she didn't talk to me for months at a time afterwards because she was so livid that I told our parents. I thought we had worked through our issues and still continued to welcome her into my home and be there for her even with how she treated me. In my mind, she's a teenager and just doesn't understand the dangers yet, but someday she will. She officially broke up with this guy about a year ago and has been dating many other people, which I understand, but it's gotten to a point where I've recognized a pattern where she dates these people just because she doesn't want to be alone. Every single person she has ever dated has treated her very poorly (the older guy obviously being the worst). Now fast-forward to the last few weeks. She officially moved in with me in July. Mind you I have lived out of state away from our family for about 9 years now. The state I currently live in requires travel by plane; it would take a day or two to drive from where we are. She decided her car wouldn't make the trip so she packed up everything she could and flew here to live with me, find a job, and attend college. She's already enrolled in classes at the community college here and started applying to a couple of jobs when she got here. That was a rule to be able to live with me, you have to get a job, and you have to be in school. I'm also in school and work full-time. I told her when she arrived it was finals week for me and I wouldn't be able to hold her hand in getting enrolled in classes and finding a job because I just have too much on my plate and told her she needed to handle this sort of thing on her own because that's what you have to do when you're an adult. I did, however, tell her I could give her a ride to the school and different places like that because I understand she just got here and doesn't have the money yet to buy a new car, which I did do. Otherwise, the majority of the time she's been here she has just sat in her room on the phone with yet another guy that she met online and hasn't really put much effort into getting a job, but it's only been two weeks so I didn't want to give her a hard time about it. Last weekend, I finished my finals and was so excited to hang out with her and help her more with things like finding a job, getting her set up with financial aid at the school, making friends, etc. This past Monday was my birthday, and my sister decided to tell me she has booked a one-way flight back to our home state to meet this guy in person that she just started talking to online about a week to two weeks ago. I was hurt, scared, baffled. I couldn't believe that she was yet again putting herself into a dangerous situation and having no regard for me or the fact that it was my birthday and knew telling me this would upset me. Oftentimes throughout her childhood and now early adulthood, I've seemed more like a parent to her than a sibling. When she told me, I did take some time to cool down before immediately popping off, but by the end of the day, I couldn't take it anymore. I did tell her exactly how I felt about it, about how dangerous it was, and it was not in her best interest to leave when she needs to be focused on finding a job and starting the fall semester on August 18th. She immediately started crying and deflecting, saying, "Oh no, I'm coming back before classes start. I just didn't have the money for a round-trip ticket. And I'm not going there just for him I'm going there because I miss my family and want to tell them bye." I told her I did not believe her because when she first told me about it, she said she was going there to meet him, but now the story has changed because I explained how dangerous that is. I absolutely refused to let her lie to me like that. We talked for hours about this and the way she treats me (she has a history of using me and not appreciating everything I do for her). I've signed a lease on three different 2 bedroom apartments to make sure I had space for her to live with me when she was ready, and over the last couple of years she's been very wishy washy with me about when she was actually going to move and has had no regard for the time, money, and emotional labor I put into this relationship with her. So I took a couple of days and decided I would not be willing to take her to the airport because she said this guy paid for her flight and would be the one picking her up from the airport. I told her she could find some other way to get to the airport because I would not be a part of her putting herself in an utterly dangerous situation with a stranger she met online. She seemed like she understood how dangerous it actually was and said she would get one of her friends to pick her up from the airport. She called one of her friends and promised me she was going to pick her up and that she was going straight to our dad's house. So I reluctantly took her to the airport that night. It was a red eye, so I took her to the airport, came back home, and went to sleep. When I woke up I realized she turned her location off for me. I thought Hmm, that's weird and immediately had a horrible gut feeling. I called her, no answer. So she texted me and basically said she landed safely and all was good. I was like, okay, well, where are you? Why did you turn your location off? She said Oh, I turned it off for everyone because no one except Mom knew I was coming. I'm like okay? That makes no sense, where are you? She deflected the question again. So I tried to video call her. No answer, says she's busy. So I said, I know you're with him, and if you're not, you can answer the video call and show me who you're with to prove me wrong. She refused, saying she was busy. So I said you have about 2 minutes to prove that I'm wrong or I'm calling dad and telling him exactly where you are and everything you've been doing. You have no idea how dangerous this is that you are sitting in the car with a complete stranger. She responded, but kept deflecting the question, so I did exactly what I said I would do and I called our dad. He tells me he had no idea she was coming and that he was sitting at his house and she hadn't been there all day. Mind you, she landed at 6am local time, and this was at about noon or 1pm local time that I realized that she lied to me because she needed me to take her to the airport because she didn't have the money for an Uber/Lyft. I called her out for lying to my face the night prior, and if she didn't own up to the lie, she would not be welcome back in my home. She just started texting back, saying Seriously? You're really going to ruin our relationship over this? I said, I'm not the one ruining the relationship, you are because you made the active choice to lie and manipulate me. And I blocked her. Blocked her phone number, blocked her on all social media, and in any way she could contact me because I'm SICK of her lies, I couldn't hear yet another one. Our parents were able to get her to tell the truth after more and more lies that she was with him and stayed with him at his house last night and refused to see any of the family that she supposedly missed so desperately. The advice I'm looking for here is, should I keep trying to help this girl and let her stay in my home after all of this? I've literally been in tears all day yesterday and today because I never wanted to kick her out or block communication with her. I fear that if I don't put my foot down and stick to what I said, she will think she can continue with this behavior. On the other side, I'm worried that if I don't help her, she will absolutely ruin her life and get severely hurt by one of these guys she keeps meeting online. I also just found out through our mom that she has tried to contact me and I feel horrible about blocking her, but as I said, I could not hear another lie from her. I certainly don't want that to be the last conversation we ever have, but I'm really really not sure when I should unblock her and if I should continue to tell her she can't live here. I'm so sorry that this post is so long. Thank you to anyone who reads it. 🫶🏻