Wrong billing amount and date

September and October Telkom increased my monthly bill with R250 without my agreement from an instalment of R423. I called to find out why my bill was high and they told me they sent me an Sm's offering to increase my airtime with R250 and because I didn't reply it means i automatically agreed to the offer. I reversed those transactions for 2months and I paid them their monthly instalment. November they sent an Sm's to say my instalment for that month will be R62 however that R62 didn't go off on month end. a week later on the 11/12/2015 they debited my account with R993 I called them to find out why that amount after they said I only need to pay R62. I logged a complaint wanting to know why are they now debiting wrong amount and on a wrong agreed debit order date. the feedback I got wasn't satisfying. From then they have debited my account on random dates and they have been debiting R993 and 862 which I don't know where it comes from. the only feedback they gave me was that they can't debit month end as I have put a hold at the bank then I asked them how can I stop the instalment I know to go off and allow the amounts I dont know.They owe me R700 of bank charges and no refund yet.