Credit Card locked

I was R100 under my payment for my FNB Private Clients credit card. An agent called me and told me so on the morning of 6/11/2015 - she asked me when I would pay and I said immediately which I did. I paid the whole outstanding credit balance as I do most months. When I tried to use it later that morning, I found it had been locked. I called my private banker who had it unlocked. He then told me it was an automated system lock, which I know cannot be valid due to the agent calling me. I use between R20000 and R30000 per month on my credit card and am appalled that firstly they would have an automated system that locks for less that small amount when I have a limit of R100000 combined. <br> I am very disappointed considering I am a loyal FNB customer for over 20 years and expect better treatment than that. I would like someone with decision making power to contact me.