Sounds like she's content to keep her options open and play you and this other guy off against eachother.
I would disregard anything she tells you about whether she's with someone else or not and why... all you can be sure of is what you see with your own eyes. Assume the worst about her or what she claims for everything outside of that.
As far as getting your things back or your money, you might as well assume those things are gone. She's unlikely to just give them back, because she knows as long as she has something you want, she has leverage against you and can keep engagement going with you.
does she have anything of yours that's really valuable or irreplaceable? Was it money you need? If not, and if you want a clean break, I would just drop her things off and then block her, and consider your things donated to the mentally ill.
If you DO need your things and money back, I would play hardball and tell her you'll turn her stuff over once you get yours, but not until then. And don't engage in any discussions unless they're about setting up an objective time and place to meet and exchange things... preferably somewhere in public where she won't be able to make wild claims or a scene without you having witnesses there.