Disgusted in FNB's customer services!!

I am utterly disgusted in FNB’s services lately. I had a sort term loan with them which I paid in full on the 13th of December. On the 18th I noticed that they deducted another month’s payment and added R141 interest which should’ve never happened, because there is nothing outstanding obliviously and they should have done their job and allocated the payment already. I immediately queried the deduction and only came nowhere with the agents. Only got instructed that I must request a refund the next day but they are the ones who made the mistake. Anyways…. The day after, a lady told me that I must give it 48 working hours for the debit order to bounce back which also never happened. In between I have queried numerous times, spoken to 100’s of agents which had snotty attitudes and only pull up their shoulders instead of helping the client. I spoke to a lady then around the 24th and she then said that the refund was escalated and it will take 5-7 working days to be paid back. It will be paid back today, the 31st. I checked my bank account and still no refund. I went on secure chat again for the 100th time and still got no where as they keep on transferring me to another agent. Only to hear that they escalated the problem again, the refund was loaded on the 19th and that they have some problems with their system but no one can give me a straight answer why I must wait 2 weeks for my refund. A refund never takes this long! I am so fed up with FNB’s customer services and am in search for another banker as they don’t take their clients seriously or worry about sorting the problem out at all. Also, I will not give up until I get my money back!!