FNB CHANGES MY PIN AS THEY WISH!!!!

FNB issued me with a new card and new pin. Weeks after using my card, they sent me a sms to change my debit order date to match my pay date, to which i rep**** 'NO'. Fnb still went ahead and changed my debit order date. When I asked them to correct this they put me through to a validation system which rejected the pin for my card. I told the consultant that this is the pin they issued and it always worked. After logging onto internet banking I realised that THEY CHANGED MY PIN as well. This is breach in security and when I notified them they said it was a card issuing error, which is not true as this happened weeks after issuing the card and me using the card. They then just said i must view my pin and change it as I wish and it should be fine. I viewed my pin and attempted using my card, to which is said incorrect pin. Causing me much embarrasment in the shops. Does FNB be know their limits as to the extent of a customer's confidential information. I have not ever given consent to FNB changing my pin!!!!! I would not recommend this bank to anyone.