Paying for no service

I am so disappointed.

3 months ago I opened a uncapped wifi contract with MTN The delivery was a complete ***** up but once I had it everything was okay for a month. In the first month of having the router, the router stopped working. I then sent the router back to mtn to try get it replaced as it is still under warranty. But after 2 months I have still had no success. The sales lady helping me has given me great service but mtn has not yet taken the router to be sorted or done anything to help. I have been paying for the contract every month without receiving any of the services I am paying for and I am now very upset. I have tried speaking to the technical department, sales reps and anyone in my power but no one can help me and if I just stopping g paying then my phone will be suspended due to it being on a linked account. I wish someone would just help me!