Dstv Bad Service - They doing this because they don't have competitors

I have app**** for a payment plan with Dstv which was approved and they delivered my decoder. The installer from Dstv came and install and activated my decoder. To my surprise, my services were disconnected. I phoned Dstv to find out why. They told me the decoder is not on my name and the decoder is owing R7000 and I must pay that amount to do the change of ownership. I told them the agreement was to pay R549 for 24 months. They said the person registered on my decoder is owing Dstv R7000. I suspect ***** and I want Dstv to sort this out or cancel the agreement that I have with them. My services are suspended and I must pay the first premium by 25/02/2020