Fnb incompetence

On 3 may I was paying suppliers and knew how much I had in my business account. Next day when I logged in I saw that the balance in my account was R6000 short. There is no records of the R6000 missing but my balance was R6000 short and it brought my business into a loss for the month. I tried to call fnb customer care but they are *********** that you cannot get through to them. It takes 15 minutes to get through and the call just gets cut after waiting so long. I will move all my accounts to another bank because we can never win with fnb. Capital is just disappearing from my bank account with no records. Strange