Sorry we can't help you

I am rather upset and disturbed by the lack of understanding and willingness to help from FNB. here's the story, I have a credit card that i have been paying off diligently and have been able to pay off R 10K i then contacted FNB to decrease my credit limit BY what i had paid off and i will continue to pay off the remaining balance, they said "sure no problem can do" next thing i know they decrease my credit card TO R 10K and due to this it appears that i have overspent on my card, so i called them to have the issue corrected, kept being pushed from pillar to post and instead of helping they tell me that i can make payment arrangements to pay the overspent amount. the error was on their side, now i am the one that has to run around to try and fix it. i feel like closing all my accounts with FNB, i use to love banking with them.