Question about hottopic return policy?

I recently got a shirt as a gift from hottopic, but it's the wrong size. Because it was given to me it no longer has the tag and I don't have the receipt. I think I've heard that you can return it for store credit? Is this true? Should I just tell them it was a gift? Also I forgot to clarify with my friend but I think she used some sort of discount to buy the shirt. It wasn't on clearance. Would this in any way affect whether or not I could return it? Thanks in advance.