DSTV incorrect billing

In April won a DStv free upgrade, that’s were the nightmare started, there have been so many payments and payments reversal on the statement, have been paying every month and now in July I’m being told to pay R1801, where is it coming from whereas I’m only paying for 2 compact subscription and one insurance for R35,made a call and was giving a reference but no one came back to me until it was disconnected this morning, made a call again and still cannot assist, they telling me of investigating yet again!