ATM ERROR

On the 10th of October I did a card less withdrawal at an ATM in Green stone valley. I tried to withdraw R7500 and the machine only released R4000 meanwhile my account got debited R7500. I called customer care and was told it would be reversed in 5 working days. I have been calling FNB everyday because the reversal has not been done and they keep telling me they investigating. Surely the so called investigation cannot take this long, unless someone is not doing their job. I am not pleased with this and its a huge inconvenience on my side and would like to have it resolved with immediate effect. FNB service is getting worse by day!