don't trust FNB daveyton branch(inside jobs) on our money

I have been banking with fnb for more than 15 years until recently when someone started to buy airtime using cellphone banbanking with my money. I went and requested a bank statement that showed this person bought R900 worth of airtime (inside job). I was told by a lady that worked there that I shouldn't change my number but I did since I was blocked and told my number was imported and til this day nothing has been done about this case...yesterday I tried to draw R6000 and it said insuffient funds, I had R7445 which meant approximately R3000 was drawed and to my surprise I didn't receive a notification which means it's a inside job...fnb staff were unhelpful with my first case of theft and I received no advise on how to handle my case nor did my money be replaced.