FNB wanted to charge me for a favour which I did for them

I am FNB customer for almost 25 years but have to think if I shall stay with them or rather go to another bank. Their branch in Somerset West ordered 1, 2 and 5 Rand coins from me for the last week as they did the week before. I changed 30.000 Rand in coins for notes and they were happy. Last Thursday I brought them coins again which they ordered. Then the branch manager saw me at the teller and said that they can not do that anymore for free. This would be the last time and next time they would have to charge me. I could only wonder as I save the bank a lot of money as they don't have to order the coins from the cash center but told him that I accept and bring my coins to another bank in future in case I have some as they would not charge me. Just before everything was counted he came back to me and told me that I can only deposit the money in my bank account and that I have to pay a fee. This would have been 830 Rand! So I would have to pay money for saving the bank costs which they would have to pay. I found out that they would have paid about R 2.500 to 3.000 when they get it delivered. I was so upset that I took all my coins back. About 80 kg!!! I told the manager that this is very unfair business as he can not order coins and then charge me for the favour which I do them, specially because he changed his mind within minutes. No chance. He did not care at all. I told him that I will close all my accounts with FNB and he simply said that I must get a ticket and wait for the next available consultant. How is that? This arrogant behaviour in the name of my bank where I was always happy with. I complained at the FNB website and a few days later someone came back to me. I was told that I can only deposit money in my account and have to pay a fee. Why don't they tell me those things before I bring them the coins and why does the manager even confirms that it is free before he changed his mind. It seems that they don't even read complaints properly. No excuse at all. Not only that they make their own rules and change their minds within minutes. To complain was a waste of time as they are too careless and not interested to solve the problem. Seems that FNB has too many customers if they can treat customers like that.