MTN Total Lack of Customer Service

I have been an MTN client for 20 odd years. I have been trying to do a SIM swop for a contract for which I am paying for the last 3 weeks. I first completed the transaction three weeks ago at Benmore Gardens and the SIM has never been activated. I have been to 3 different stores including Eastgate, Hyde Park Corner and Benmore Gardens 4 times with absolutely no joy. The activation is not going through and each time, all everyone does is log another ticket. Or tell me that they cannot help me as the last ticket is still open. I tried calling the Contact Centre using several different numbers, and keep getting pushed from pillar to post and cut off with absolutely no joy. Benmore Gardens is unable to help me and then the Manager "knocks off early" while the store is filled with customers. Your service is appalling! I am paying for a service which I don't have and you staff don't even bat an eyelid.