Nedbank - No response to formal complaint

Nedbank N1 City changed my bank account from no fees to a fee based account without letting me know. So, after a huge struggle the account was changed but Nedbank is now ignoring me to refund the fees. Even after a complaint and many promises! I even logged a formal complaint as required by financial services legislation and the code of conduct and Nedbank is just not responding. Nedbank, this is a contravention of legislation. What more must a person do to get the decency of a response and making good on your promises?