Unauthorized service

I have been using a PVR decoder for over 2 years paying for a DSTV Compact. For the past 2 months I've noticed that the amount that am paying is changing every month. When I inquired as to why am no longer paying the R399, I was informed that I have activated the recording service using DStv self service. For starts that service I last used it when I was setting up my account and never again I used it. I want my money to be refunded as I did not authorized these additional services.