Not impressed with Old Mutual

In the beginning of Feb I emailed Old Mutual among other places to inform them of change of my banking details. End of Feb surprised when they tried to deduct off my old account.... so I have debit order rejection fees. After this I have sent no less than 10 emails explaining that they will have to start deducting again at the end of March as I now have fees to pay because they did not do their job (all the other places did) Now after all this i receive a call now from them trying to deduct my account (wrong account) and that i should rather go into the branch to change the details. I have also informed them that if they double deduct my account end of March I will cancel my policy as this is not my fault.