Debit order continues after contact cancelled

I converted a data contract to pre-paid (apparently that's how to cancel a contract) in August. As the debit order still went off in November, I called the call 011 912 300. After spending ages on hold, I was given a reference number and told that someone would call me back within 24 hours. After 24 hours I called to follow up the call only to be told that I cannot be helped as the contract is in my husband's name and that we need to go to a branch to give me permission to access the account. The operator said he would get his supervisor to call me. This did not happen, The debit order comes off of my bank account and it will probably be another 2 weeks before I can get my husband to a branch. I also cannot expect him to spend 30 minutes on hold to your call centre. MTN is now *****ing my money on a monthly basis as they have confirmed that the account has been converted to pre-paid (on the 3 occasions that I was allowed to get this information). Once this is resolved I will be moving both of my numbers to another network.