Credit owed but not paying back

I have got a credit on my old credit card that I have been requesting for 2 months now that they transfer the money in to my account. The account I use is in my wife's name and have therefore been told to send relevant documents which I have done on numerous occasions. I have not heard anything for weeks now and do not understand why they are keeping MY money! They are quick to phone if we owe them but when it is the other way around it is impossible to get my credit back!! Will never use ABSA for anything ever again.