Honestly, I would just go back on another day and try to find another employee. I've had issues trying to do returns or certain things and some people are just going to give you grief. I work in retail and I know that most of the time, no matter what the store's policy is, we generally have to try our best to make people happy (within reason, as long as they aren't being mega-jerks, and sometimes even when they are!) Maybe that guy was having a bad day. If you go back and a different person does the same thing, then I would raise an issue, talk to the manager etc. Don't give up!