R2 000 missing from my bank account without a trace.

R2 000 is missing from my bank account. On the 23rd of March early morning i keft my house to go to brits on the way to brits i poured petrol which reflected my remaining bank balance. 30 min later R2 000 had disappeared in my account with no trace. The last transaction shown on my bank account is the R500 i poured at the gad station. I went to the branch and they couldn't tell me what happen to the money but it had dissapeared. I was told virtual card transaction may be th problem however when we calculated, it still left us with a shortage of R2 000. I called the ***** department and the lady said she sees no transaction and that she cant do anything as no transactions are visible. It is concerning to hear that money is being removed from my account without my knowledge and there is no trace of it. It really leaves me wondering how trust worthy FNB Really is that money can dissapear without a trace.