FNB

I bank with FNB for a decade, all of a sudden I have minus for monthly fees, but I bank with them and they told me that I sign the contract with on the 23rd so they have to debit on that date, so they not advising their client of that loophole, its a ******* because now they have monthly fee to charge me in which its ohk and the minus I don't get it because I bank with them for 25th of every month on this day they decide to go debit on the 23th January 2020, not even the 24th, so now I have to pay double, please people advise here, is there honest bank in RSA need to move.