My Ex-Roommate Left a Large Bill

Burner account. For the past year I "had a roommate" in the sense that 4 months into living together they made me feel unsafe and I pretty much didn't live there after. We had a move out time end of May and I got the security deposit letter in the mail and I about fainted reading that $3,000 was still owed. Here's the whole situation:

Things were great before we moved in, everyone was on board. There was me, roommate 1 (lets call them John) and roommate 2 (Jane). Moving in things were good, and we had a few issues every now and then in instances where I'd be messy and try to fix it when brought up by John. I always tried to put my best foot forward in approaching those situations. Though after a while more drama kept appearing. John started having beef with Jane's partner for little to no reason and Jane quickly started avoiding being home. Around the same time, John wanted to bring their cat to the apartment which had a no pet policy, but Jane and I agreed just under the condition they worked to hide the cat and take up after it. Then a kitten came along sometime later which felt a bit more iffy.

After a while, John started accusing me of things around the house and beyond. I had gotten involved with a friend, it ended messy, and there was a lot there. I started feeling less comfortable so I soon also spent less time there and started being around my now boyfriend more. Then weeks go by and I'm not gone fro the apartment, just in and out to eat when my bf is rarely busy, work, or grab clothes (maybe once or twice a week). Eventually I notice that the apartment just gets messier despite me cleaning, doing dishes, etc when I'm over briefly. I try to confront John via text (I hadn't seen them face to face in weeks really) and they start going off on how im incredibly messy and none of our friends like me etc etc. This leads to a large fallout and me then never returning despite grabbing clothes once a month in and out.

During the time that I'm out, I notice that the place is still messy continuously and would only be clean if there were signs of other people going to be there. I started shrugging it off as John's problem. After a long time of no contact between John and I, we all have to talk about moveout stuff maybe 2 months prior via text which goes fine. During the month of the move is start going to get things and i notice the cleanliness has gotten worse. There is always food out, there are roaches everywhere except in my room pretty much (no idea about Jane's room). By then I get so dizzy just being there that I'm focused on being in and out and getting all of my stuff moved. At the end I turn in mine and Jane's keys (she asked me to) and im just finished with it all wanting to put it behind me.

A few weeks later I get the security deposit letter that requires over $3,000 to pay. It's an itemized list that states a key is missing, all carpets had to be replaced due to embedded fur and cat shit, the roach i gestation costs money, there were multiple items to be removed including a mattress.

I don't know what to do at this point, the money i owe based on what I can reason on the list is around $260 which is covered by my security deposit and is honestly due to the landlord charging me for wear and tear like scuffs in paint. I don't even have contact to John now after we've all moved out. All I have would be their parent's address because ive driven them and they're a cosigner for John.

Tldr: Roommate ousted me 4 months into living together and wrecked the place leaving $3,000 to pay after security deposit. No way to contact directly.