Inability to deactivate international roaming

Firstly the consultant provided me with incorrect codes to activate international roaming, eventhough it was confirmed back a number of times. Two days later returning to South Africa Mtn is not able to deactivate international roaming by using the codes #331*0000#. Not even the call centre is able to put my number back on the network. This results in Mtn not being able to provide mobile services to me whilst I am still a paying customer. If one party performs and the other does not, this results in breach of contract. This is just another service delivery failure of multiple encounters. Please get Mtn Operations department responding on this. Call Centre not able, Branches clueless. I now need a competent staff member to assist...