Contract sim swop for ****** phone. Waiting time 2 weeks?

My cellphone was ****** 2 weeks ago. I did a sim swop the next day. With Vodacom everything worked perfect and within 2 hours I was using the sim. However with my mtn contract sim swop, I've been having numerous issues. I did about 7 sim swops over the past 2 weeks, i.e visiting the pavilion mtn store 7 times and I sim don't have a working sim card. Furthermore I was told that the person who stole my phone is rejecting the 7 sim swops and is using the data and minutes on that sim which I'm currently paying for.

On the last visit, I was told to wait 2-3 days and someone will contact me to update me on what is happening. However is didn't happen and I'm still waiting.

I'm honestly very disappointed and frustrated with the service received over what I believe is a simple matter.

Many thanks