Unhappy

I purchased a laptop from Bradlows 4 months ago . The agreement was a paying through debt order. They debited from my First bank which was FNB and later i switched to another bank Capitec. Soon after the switch i received a call from Bradlows (Philani) confirming the switch with me. That month they debited from Capitec. In October i received a SMS saying that i was in arrears i went into the Jeppe Street Branch to equire and i was told that it was a system error. On Friday the 09 th of December i received a call from Bradlows saying that i owed them and that my debt didnt go through i asked how come but the lady hung up on me. I went to the branch with my bank statement and indeed they didnt debit from the past 2 months. I questioned how come because i made sure that i spend money when all debit orders have debted, they said they had the incorrect banking details. We then called the the Head office to seek answers , i spoke to a lady called Thulisa she said she was looking into the matter and that i shoild hold the line. I held for about 45mins and she come back to me. When i tried to call again she kept hanging up the phone. Problem is its not my fault that the system changed my bank bank details. Im now seen to be a bad payer this has made my life a living hell cause im in need of extra cash but im being declined because of this, Please assist.