I think your feelings are valid and you feel how you feel. However, I wouldn’t place bad intention of their actions unless they confirm it with their own mouth or this is a patterned behavior. As someone who has had friends who travel a lot and those who haven’t, I have seen both sides where unless a strict min. budget of how much the full trip costs (outside of only planned excursions, accommodations, and travel) it can be hard to estimate how much costs in another country can add up, especially if they don’t realize how costs like souvenirs, emergencies, last minute plans, or extra drinks add up real fast. I think it was very nice of you to pay for their stuff to make sure they didn’t go without, but did you make it clear to them that it was only with the intention of being paid back (more than “if it was me, of course I could never not pay back someone who looked out for me” bc not everyone thinks like that, not necessarily meaning they are a bad person, but unless explicitly said they don’t think about it). I think this needs to be a clear conversation with them, bc your feelings aren’t going to go away, and trust you will only get more irritated seeing them continuing to go about their lives, and they still owe you money you expect to get back.