Why do some sellers do this?

A week ago (the 17th Tuesday), i ordered something on depop. The seller thanked me for buying, saying she ships in 2 days but will let me know and will give me a tracking number. I said thank you. Three days later, I went back onto depop to see if the package has been shipped as I don’t receive notifications and when I went into messages, the listing has been removed and I was unable to reply to the message. Took it up with depop then took it up with PayPal, got my money back but on Saturday night, I got an email saying the package has been shipped?? I have no idea if it’s just saying that or if it’s is actually the package but I still can’t message the girl and there is no tracking number. What should I do? Is it normal for sellers to remove listings and make it unable to reply to messages?