Thieving bank charges

After being a client for more that six years, and maintaining my account, FNB decides to penalize me for an instance with more than the value. Complaint Reference "***NF". I would like to stay a client, but at the moment I am treated like an enemy. Yet I pay quite a lot of bank charges. If the charges, WHICH WAS NEVER DISCUSSED WITH ME when I opened the account, I will realize that FNB does not value their clients and will be forced to move my account. If the charges were discussed, this would never have happened.