Worst Cancellation process ever

Possibly the stupidest cancellation process I have ever come across. My husband has been on the phone for the past two days to try get through the the MTN retention department to get his contract cancelled. He was on a promotional data contract if we dont get it cancelled MTN has said the installment will be going up from R299 to R1600 for his data deal. We are trying to get this cancelled. We have been into the store and they have log it and given us the reference number. We have been sitting on the phone and just rings or line drops. We have emailed and no luck no one is helping us I honestly dont know what to do.