Pathetic service from telkom

Service is pathetic. I have a contract with telkom. My agreement with them was for R328 per month but every month the amount just keeps going up. I asked them to cancel the debit order so I can pay it cash every month as I've been doing so far with no problems. as its more convenient that way. Get sms that says my account is in arrears which can't be because I have all the slips to prove its been paid. Asked them to call me to sort out why it keeps going up but to my surprise they dont even care to call you. If they dont cancel the debit order I will be closing the bank account. I would not recommend them to anyone even if my life depended on it.