Delinquent MTN

I've been trying to contact the MTN retentions department for a month as well the MTN Zevenwacht branch to cancel my contract and there's been absolutely no answer. Last month I had no internet connection for about 2 weeks, went to query instore at Somerset Mall and they were "offline". Needless to say, I had to pay the full monthly subscription. I visit different branches and my details are never updated. We're paying for putrid service and the cherry on top is that they're telephonically unreachable.