Overcharged and no accountability from dstv

They have been billing me R538 for compact even after I called them 3 months ago telling them that my pvr is not working and they must cancell the functionality which they said they did but didn't, 2 days ago I called asking them about my fees they comfirmed I payed R110 too much for 3 months theyll credit my account and I must pay R250 I payed it but to my surprise my TV still not working I called again yesterday and spoke to some 1 else who promised me that the manager will sort it out and call me, I'm still waiting even now,