I think you are extremely nice person to worry that repaying you would put a burden on her. But isn’t it a burden on you to part with probably a significant sum of money? I think if she spent that money, then it’s up to her how to pay it back. And with tickets I also find interesting that you still want to go somewhere with her after she stopped communicating.

I am not saying she is a scammer. She would be one if she didn’t pay you back. At this point she took the money and went underground not giving you heads up how she plans on pay you back or resume sessions. That’s a bit unusual

I don’t think you becoming friends is to blame. Her behavior isn’t very “friend” like.

Now again I don’t know if she is a scammer. But she owes you some type of communication at this point. And no you don’t owe her anything.