What should I do about the fact that I have someone's credit card information.
Well tell me what you want to do with the credit card information?
I am not sure what I'll do.
You should not keep someone else's credit card information. It's best to destroy that information so you aren't tempted to use it, and that it doesn't fall into the wrong hands.
I see. Hm... Maybe I should hang on to it just in case.
I don't think you should be keeping it, it's not your information to have by the sounds of it. Why not just erase it and move on?