Charges on account

I have a serious issue with FNB LIFE and FNB Funeral cover it looks like they don't adhere to debt order dates, i just spotted that my account is on minus and that I have been charged for #items paid no funds for both months this ruins my statement. who gave them authority to debt the account on the 3rd. 4th and 5th. They also double debt my account, infact I would like to cancel the covers coz this is not the 1st time I complain about them. FNB please reverse this bank charges my account has incured for for two months from FNB LIFE and FNB Funeral cover.