Account in Arrears

My father open an account with game store and did an additional card for my mom my mom she has been the one paying the account all along then on the 1st of July she decided to pay with the additional card before paying she asked the cashier if its fine paying with the additional she said yes she paid with it. then om the 13th of July my father gets an sms saying that he didn't pay he goes to Jabulani Mall to find out what is happen with the proof of payment they called the head office to find out what is the matter and they told him that the money that was paid is floating and was told to go do an affidavit he did that nothing last week friday he went again and was told they is nothing they can do and also blocked the additional card that has R1000 that is floating all my father needed was for them to move the money to the account thats all.