FNB cheque account problems!

I had a problem with the money that disappeared in my account last month and thank you for the quick response and the money was restored in my, problem is that the same thing has happened again, last night I had money in my account and today it's not there, the balance is 0.00, can you please get to the bottom of this issue....or maybe it will be wise to change banks coz this is becoming a headache