Incompetence to handle sim swap

I upgraded on MTN via Mobile Plus. Everything when good and the phone was delivered on Thursday (08/10). When I opened the package, the wrong SIM card was sent with. The phone operates with a nano-sim and they sent a micro Sim. So I got a new unused (still in the case) card at my employer who had extra in the safe. When I tried phoning MTN to do a Sim-swop they sent me from this place to that place without success. After phoning my nearest MTN shop (98 km away) they sort of helped me. On Saturday I drove to them and all they told me is that I should wait, it can take up to 24h. I am still waiting from Friday that they had sent the request until now. This morning when I phoned 808 to give my reference nr to check the status they told me to go back to the shop. I am very disappointed in your service MTN and I spent a lot of time and money on the phone as well as driving to your shop without success. How am I suppose to be a happy customer with this ****py service?