Dollar General

I bought a green dot debit card in the Dollar General in Strafford, TX 79084 just to find out that the $50 that I deposited never were deposit and now they don't want to give me my money back and I want a refund I spoke to the manager but I'm not getting anywhere to make things worse the serial number on the receipt it's not the same is there one in the debit card I don't know if the lady give me the wrong card or what I'm fed up with waiting it's been Almost a month