Disgusting service

This morning when I went into my FNB app my balance was -R966.00 this is impossible as I had money in my account. Then when I looked again I had R1896.00 and the sum of R1072.00 was taken from account. I phoned FNB and I was told to use the service on the app where I was transferred to 5 different people who had no idea how to help me! This is absolutely disgusting service and my issue has still not been resolved.