Poor service from DSTV

If I could've rated a zero I would. I've been paying my account religiously every month on the 1st. Today they tell me I owe R1300 because of a R500 I didn't pay the previous month. I have asked numerous agents for transaction history, and they don't forward me the history after they said that they would. Can't wait for my contract to end so I can get rid of these parasites.