Poor service of telkom

Ever since December when I changed my banking details they have been debiting out of old account and adding fees for a debit order that did not go off my account where as I gave them new banking details 3months back. Eventually this month the debit but fail to debit the full amount leaving my account to be disconnection due to account being in " arrears." With all due respect, this is the poorest service I have ever got ,the agents in the call centre that do not update your details correctly and left you with penalties on the account, highly unfair, customer service is poor. Please don't use their services