Very Disappointing service from FNB

it's been 3 weeks now since logged a call with no feedback at all from the Debit card authorisation department, I had an outstanding payment that I wanted to reverse before the merchant took it as I have noticed that I have purchased from a **** site and the money was there for 3 days on pending but guess what FNB never bothered to check the call that I have logged and you can't even call the department. i have sent emails to follow up even today no response at all.