I will never ever become a client again!

I had a cyber sleuth account with this people for about a year or two and and everything was fine up until the end of my first year with them as they would skip debit orders and only debit my account when they feel like it. The issue at hand is that I finally managed to cancel my relationship with them due to their ********** billing issues and I was transferred to an Afrikaans lady in their account dept who had no clue what she was doing and wasn't shy to advise me to go to the bank to reverse the extra debit orders that were deducted from my account without even considering how that would affect my credit record) as there were two deductions in a space of a week and she didn't know why I was debited. NOW Altech keeps sending me sms's that I owe the R380 for missed payments when in actual fact I have no account with them. If in actual fact I do owe you could someone please call me and explain to me what it is that I owe them for. BUT A PIECE OF ADVISE TO FELLOW CLIENTS, DO NOT ARRANGE DEBIT ORDER WITH ALTECH CAUSE THEY HAVE A SERIOUS BILLING PROBLEM THAT THEY DON'T INTEND ON FIXING!