Very bad service

I have 2 decorders that were in compact subscription then on 28 August, I contact dstv via Facebook to downgrade both decorders to access and I assured that it was downgrade from 1 September but I was surprised that I owed R560 while access subscription is R120 per month Now I'm told that one decorder downgrade was not successful Whos fault is this? Why should I pay for the agent mistake?

This is really unacceptable