Frustration

Capitec Bank is failing to help me and is withholding information from me. They added an amount that was not supposed to be added on my loan account with them. I have queried this and no one has cared to explain why. I want the money refunded to me as they were not supposed to have added it, it was an internal error on their side. When I call and go through the statement with them, they tell me that they can't explain what is happening. I show them what the error is on the statement but they go around in circles, this is very frustrating.