MTN is a nightmare

I received a call a few months ago from MTN offering me a router and data plan. I accepted it and everything was concluded, before ending the call I asked the agent to confirm that this was a month on month payment plan as I was not in a position to enter into a contract. When I received my router it did not work. After a week the router was still not working, I phone MTN and was informed that I had to a fee for the device to be activated and because THIS WAS A CONTRACT for 3vyears!!! I requested for this to be rectified and was informed that the contract was done by TEVO on behalf of MTN??? I then went to MTN Eastgate and returned the device and requested for the device to be sent back and the contract to be canceled. The device was taken, I received a confirmation email, however I am still being billed every month. I have requested for the Eastgate team to assist me on several occasions, I even gave their branch manager my number but they are now ignoring me. I sent an email to their complaints department but no one has reached out to me. I have been so loyal to MTN but they do not care about their clients.