Personal loans arrears

FNB has deducted the whole outstanding arrears from my account without consulting with me and without my authorization - I have tried to make payment arrangements with no avail. I have phoned the call centre to discuss the matter, and the teamleader Emmanuel Ntshangase said that I should send him an email regarding the incident and he will sort the matter out. I have sent the mail on 8 April and to date did not have any response from him. When I phone, Emmanuel is not available. I would like this to be sorted out, as this is not according to the terms and conditions as signed in my contract.