unfair billing

it is with utter frustration that im writing this review, my mom is 67 years old and has been a dstv subscriber for so many years but since last year when they introduced a promotion phutanami something like that her dstv account has been totally overcharged, after so many call and eventually speaking to a manger last year December we were assured that the accounts department will fix this but still nothing, I pay her dstv account every month on the 15th and sometimes before that but then I just see she owes r800 when she is on compact when she enquires they tell her she has an outstanding amount from the previous month which cannot be possible as she receives an sms as to how much to pay and she always calls before we make payment . so it happened again in march and decided to downgrade to family package guess what we checked her balance over the weekend she owes r900 for a family package off r290 when she called was told about price increase and owing on pvr services, please explain to me how on earth this is possible,i want this sorted before 15th april because she will not be paying for full bouquet that she is not even on, this is a total ******* from dstv.