First National Bank SA the worst bank ever!!!

I am very ****ed off with FNB!!! As a loyal customer for 14 years this is how they treat people. I took out a loan on the 7/7/18 with them and agreed on an instalment and was told via sms that the first instalment would go off on the 31/08/18 and an initial amount would have to be paid and there after it would go back to the original agreed instalment. By the 04/09/18 the debit order still had not gone off so being the loyal, trustworthy person that I am I called to find out why it hadn't gone off as I did not want to be in arrears. The consultant told me that they tried to debit on the 25/08/18 but it bounced. Now I never agreed to the date of the 25th but was told it had to go with my salary which is deposited on the 25th which I said was fine and I couldn't get an answer as to why it bounced because that's when my funds are deposited. The consultant advised he would load a manual debit order that should go off after a few minutes. So on the 05/09/18 still nothing had gone off so I called again n asked to speak to a manager to help try assist all of which were busy on other calls conveniently. The new consultant tells me she can see the manual debit order was loaded and also bounced. Now is this my fault as there are enough funds in my account which the consultant confirmed but couldn't give any explanation as to why it had happened. Further more the instalment had increased because the debit order date was changed - who requested this change? They can't tell me, if it was me, fine but I don't recall making this request. Is it so wrong of me to want to pay what I agreed to pay, terms by the way set by them? Why should I bare the brunt of their incompetence? Now I have to inconvenience myself and go into a branch to seek help and all because I have always been a loyal customer, never having arrears and now being afraid of having arrears and being blacklisted for something that isn't my fault. My husband has been telling me for years that FNB rips people off on bank charges and who knows what else and that I should "switch" to Capitec and I have always defended them. I'm beginning to agree with him and think siding with them was all in vain. Maybe it is time to switch.