contract sim swap frustration

i went to mtn carnival mall, the one nearer woolworths for a sim swap on the 28th August 2019, trusting that all is well didnt bother to check if the card is working, on Tuesday the 8th October i tried using the sim card but found out that it is not registered, i went back to the shop the following day to find out why the sim in not connected and ended up spending some time while they try to get me connect and eventually the did another sim swap but the following day its still not connected, when i go back there was told they communicate with the head office and ask the to do the sim swap and on Monday the 14th i called again to find out the transaction has not be done and they really dont know what to do. its a frustration that mtn is unable to solve a simple thing like sim swap services, i need to use that data but i find myself frustrated by the whole thing, Kindly assist