How to deal with a dishonest cousin who took my money?

I am currently in Asia visiting relatives, and am staying with my uncle and his family. While there is some bad history between my uncle and my parents (he owes them money and still refuses to pay them back, despite being financially established), I have been trying to distance myself from any negative feelings. I thought my two cousins, who are my age, were good, honest people. However, one of them took me to the nail salon and we both got manicures and pedicures. When it came time to pay, I thought we would split the bill evenly, but before I could take any money out of my purse she had already paid the bill in full with what I thought was her own money. I protested vehemently and tried to pay her back, but she refused my money and smilingly said it was okay, because I don’t visit here often and that I was their guest. She gave me the impression that she had been the one to treat me at the nail salon, and I kept feeling guilty about it since I know she’s still in school and not working yet. So, when she was out, I went into her room and put the money for my share of the manicure/pedicure on her dresser. When she returned, I told her that I didn’t want her treating me for the mani/pedi and that I had put the money for my share in her room. She responded with a smile and said, “Thank you.” I have recently found out (by asking my aunt), that my aunt had given her money for us to use at the salon. I did approach this matter with my aunt as I wanted to clarify who exactly was the one who intended to treat me at the salon. When I told her that I paid her daughter back and that she accepted my money, my aunt became defensive and said that her daughter probably forgot and that she would have her daughter pay me back the money. I told her that wasn’t needed, but after having this conversation I am quite shocked that my cousin accepted my money and did nothing to mention that it had been indeed her mother who treated me. I am surprised she didn’t correct me when I had umed SHE had been the one to treat me. I have always thought my cousin held strong moral values, being a very devout Christian. But now I am confused as to why she would do this. I think her mother might approach her about the subject, and I am a little anxious to see how she will respond. I didn’t think she would stoop so low to trick me of my money this way, especially since I bought her expensive branded makeup from Canada and how nice I have been to her during my stay. My question is how I should proceed with this matter. Should I let it go and at least be thankful that I know what kind of person she is now, or should I confront her? Any suggestions or advice appreciated. Thanks in advance.