TERRIBLE CUSTOMER SERVICE BY MTN

I bought a new phone, which uses a micro sim and I am trying to do a sim swap through the MTN call centre. But my call never gets routed to a consultant to be assisted. I tried dialing *737# and following the prompts but that only ends with telling me I need to dial 173. When I dial 173, I get told to call again later, again and again. I only have 24 hours to do this sim swap and yet I'm getting terrible customer service.. My number has been with the network for long and I never/rarely call their call centre. If this is the type of customer service customers receive daily when they call this call centre, why is MTN regarded as one of the leading service providers in the country or Africa for that matter?!