Thievish ways from FNB PREMIER!

So i went into my online banking today and noticed that almost R900 have been deducted from my credit card for interest fees,i have never been deducted such a large amount ever since i have my PREMIER CREDIT CARD,i called in and it took 15mins to get a hold of a consultant to assist me and when i finally got to him he was not helpful and i asked to get a refund due to the large amount taken and he could not do it stating my statement closes on the 19th of each month so i go to my history and see the 19th of previous months there was no such interest taken out,i have borrowed money to get through the daily living till i get paid my salary and now i am left with nothing,this is a real **** story given to me especially after banking with FNB for over 20 years ...i cannot understand why not take out fees end month end but few days before pay day....i am damn disgusted with your services really and your motto says "how can we help you" i expect a reply to this ***** ways from you FNB and a refund should be given because it is owed to me !!!!!