NO RESPONSE FROM MTN

My husband has two contacts with MTN, we emailed them in the beginning of June to advice that we want the contracts to be switched over to prepaid as soon as it contacts end, which was on the 1 July and the 4 July. We have been struggling to get hold of MTN to confirm if the contracts were switched over to prepaid and then they even took another debit order of my husbands account at the end of June. This is becoming very frustrating, as the number to phone just rings and rings until the call is ended from MTN's side and if you go to the shops they also tell you they cant help you as they also need to go through the call center.