Appalling Service Received from Standard Bank

I have been inundated with calls from standard bank for the last 8 months asking me to pay a R12.65 amount that none of their staff members has been able to explain. I escalated the issue to their complaints department and the lady by the name of Thobeka Luvhengo kept on telling me she can't assist me because she can't verify me. Despite telling her that I have been successfully verified at least 10 times by the different agents at standard bank, why can't she change the method of verification. She refused and insisted I go to the branch despite me explaining to her that I live very far from the branch and I had been there already and they sent me to the phone and told me that they don't assist vehicle finance in any of the branches. I am forced to pay an amount that I do not know what it is for.