DStv

So September last year I've been overcharged by multichoice then managed to get my refund back then for the past 3 months they haven't been taking any money from my account and tried to call every month to find out what's going on with my account and I've been told that I don't owe anything to them and my next payment will be in January and it will be R160 so today when I got back from work my account was not working and I've been told that I owe R850 nd ive spent about R100 airtime trying to fix the problem first call to me 20 minutes without any solution then second call I was put on hold for about 8 minutes till I ran out of airtime I'm really angry and I need assistance