#PMT HONFEE 2 ITEMS ON 15/08/

On 20/08/15 I noticed a debit order of R100, ref no: #PMT HONFEE 2 ITEMS ON 15/08/ was deducted from my account. I called FNB and was told that I made two transactions on 14/08/15 for R57 and R60 and because there was NO MONEY in my account, FNB decided to deduct R100 off my acc to HONOUR these two transactions, BUT I had money in my account... I called FNB on the 20.08.2015 and got given a ref no and was told they will call me back. I called again on 24/08/15 and was told that they are still busy with my query. I called again on 27.08.15 and was told that someone from their Platinum division will call me back. Today, 31.08.15, Charity Nkosi from FNB called me back and told me that FNB will not be reversing that transaction, because of my point status and because the suppliers banked these transactions on the 15/08/15?? I don't understand this, why would I be charged R100 HONFEE if there was money in my account, surely if there was not money in my acc, my balance would show a negative amount??