Poor service

Horrible service from FNB personal loans. They didn't debit me in April and they told me i owe the errears and advised the consultant to debit the errears in May then again in May they still don't debit and again they call me that I owe them. Today I get told I need to approve the debit order authorisation which I didn't. Now the consultant says I must pay the errears or my credit score will be affected. Seems like FNB personal loans wants to blame for their incompetence.