cancellation drama, affecting my finance and credit score.

This company after giving more than 1 month notice on a month to month contract still take debit orders of my account after cancellation 4 months down the line. explaining and showing proof of cancellation does not help me and no one would rectify this. also i found now reversing the debit order from my bank that this affect my credit rating even though i don't even owe Webafrica any money. this is unacceptable. sending emails don't help and trying to call them is pointless.