Unauthorised debit & router repairs

I took a telkom adsl deal in July (R599) and between then and now there has been constant bad service.

The consultants at Telkom the Glen (and later on Telkom Cresta) were specifically told that I do not want to authorise a debit order for the payments as I would be paying cash. For the past 2 months I have had to reverse debits from them and I went and alerted them to not debit me. On the 15th of November I received an sms saying that the balance to be paid is R792, I went to Telkom in Centurion and was told that the billing department would call me. Billing did call 30 minutes after that and consultant was was not helpful at all - constantly dodging direct question and doing nothing to clear my situation: the consultant stated that the additional amount was a service fee for my debits.

I must I pay service fees to debit orders I have not authorised?

Furthermore, the router stopped working and I returned it to Telkom Cresta a week ago and nobody has given any feedback about that and when i went to go ask about it on 21/11/2017 I was told there's no feedback yet.