overcharged, told i owe more

i have recieved an email from thamsanqa amos indicating multichoice owe me about 900. he'd refered the matter to their finance section for them to refund me. i have been disconnected for a while, and today i got a mail that claims i owe them 82.00. their agents always promise to follow up, but nothing comes out of it.<br> <br> is there an ombudsman or a body regulating them where one can report them? could those who have been over-billed come together under one banner and approach a court for assistence? does the public protector have powers to invrstigate this industry?