Counterfeit notes that no one wants to deal with?

Thursday and Friday saw me drawing a substantial amount from side by side ATMS at a shopping Mall in KZN. Using these withdrawals I then paid staff on Friday. On Saturday a staff member informed us the R100 note given to her as salary that Friday was denied as payment at a renowned grocery chain as it was counterfeit. We then checked through the notes we had and found a very large sum of counterfeit R100 notes. I telephoned FNB line straight away and the lovely computer voice prompted by me with one word ***** gave me to all departments but ***** line. Eventually was told to go the branch. My husband dutifully went to Hillcrest FNB branch and asked for a manager...the teller had no idea what 'counterfeit' notes meant! This same teller informed my husband the manager would be along shortly. After an hour of waiting my husband asked another member of staff what the managers hold up was, to be told the manager had phoned in sick. Seriously.... After explaining the situation to this staff member, who enquired why we had withdrawn money on 2 consecutive days (why should I explain when and why we withdraw money), the staff member then looked at the notes and had to be educated by my husband as to which was counterfeit which was not ...again SERIOUSLY. He left with having spent 2 hours in the FNB bank and had got nowhere. So we back to square one....do we now spend counterfeit money for it to circulate. Questions..the bank directly or indirectly fills ATM with money how come they are distributing counterfeit money, missed this large oversight? Have they seriously no idea of real or counterfeit notes? When you try and do the right thing they have no idea what to do, how come this is so? Bleeding rediculous FNB...inefficient and unprofessional to say the least.