BJ's Wholesale Club

I purchased 3 items today that totaled with tax $62.81.
As I was in the parking lot my husband called and reminded me that we did not need these items right now. I went into return them and was only issued a refund for $56.40. When I questioned the clerk she did not know "why" the computer would not give me the entire amount I paid as a credit to my credit card. I asked to speak to a manager, was told there was no one to help me. How are you getting by at the Farmingdale NY location by doing this to good paying customers? I am sincerely upset by this and was just too tired to argue with the girl.