Go Wireless/Metro PCS authorized dealer I paid my bill and wanted my refund back the same day ,within hours, and was refused. Sacramento, California

On Monday, June 1st, 2010 I paid my Metro pcs bill at "Go Wireless". A few hours later, I go back into the same store and ask the same guy for a refund because I wanted to discontinue my service with metro, and was told that they were unable to refund my money because " They don't do that." I was under the impression that if YOU pay YOUR OWN bill, and YOU want YOUR refund back, YOU have three days to do so. Keep in mind that this was no scam people. I simply paid my bill and then wanted my money back. I didn't even wait one day, I went back within hours. I went myself, and I talked to the same individual that took my payment. I didn't have my recipt, but that wasn't the reason he didn't give my refund. He just simply said that they couldn't do it. If there's anyone out there that can help me, please let me know. I don't think that anyone should be treated like that.