***** someone using my card blacked on etolls and fnb does nothing about it

My wallet got stollen last month and I had to go to the bank tht same day to block and get a new card ....a week later money started to go out with tapping so I went back to the bank to complain the contacted the froud department and I got the reference number tht was only R1200 I think now a week letter it's R3800 the thing is how does a card tht is blocked get money out and does tht mean fnb does not have control of our accounts and the fact tht when I went thr they said I should just wait until the froud department do an investigation now it's 4000 rand's when I went the second time to complain the cashier told me to wait until investigation is done the way I am ruined it's so bad I cnt even pay my rentals now because if my pay comes in tomorrow all the money will be gone it's funny people who we give our money to secure are saying we should wait until investigation is one tht will be in 15 to 20 days of my money going I do not hold a card tht takes overdraft but thr is 4000 rand's our