FNB not fixing a problem!

I have a personal loan with FNB. At the end of July my loan was in arrears with 1 month. However my APP said I was in arrears with 2 months. It then gave me the option of making an arrangement to pay off the arrears amount over 6 months. However, my monthly instalment went of TWICE and I was told they could see no arrangement on their side. They told me they would reverse one instalment for me. Then, the arrangement amount went off anyway. After speaking to numerous people, my refund still has not been made and I am paying an arrangement amount even though they say there is no arrangement and the account is not in arrears. I have been expecting the refund for OVER 9 working days now. After speaking to a manager, I still have no idea what FNB is doing to fix this problem. I tried explaining that they can keep the arrears arrangement in place but then I expect my two instalments back. If they can only refund one, the arrangement amount must be less. If they do not refund me (which is unacceptable) I should not be paying an arrears amount for the next 6 months. I have tried to speak to too many people to recount and nothing is being done. If the arrangement is in place, WHY was TWO instalments taken anyway?