Showmax/DSTV ********ly taking money off my MTN account every month

Hi, I originally signed up for Showmax usin my MTN account. For the last 4 months I have tried to cancel the accout as I use another streaming service. I have tried to cancel the account with MTN,Showmax and DSTV and nothing has worked. When I go into manage my account it said it is cancelled, but I and still paying the R99pm on my MTN billing. The last time I even got written proof that the account was closed, yet 2 more moths down the line i am still paying. Please if someone has the same issue please advise how you got Show max to stop billing me for a service i have not used in 6 months. I will start taking legal steps if this is not resolved. I am highly frustrated with the shoddy service, I will never use Showmax or DSTV ever again.