Debit order not corresponding with statement

I'm currently financed for my homeloan by nedbank, this year got a letter stating I'm owing them and my bond is in arrears when I contact them they say the specialist will be in contact, they don't have a clue of what is happening, it's been 3 weeks now no call and my debit says I'm paying R7700 but on my statements it says R6600 plus R59 service fee, I call them again to ask why is the R7700 you are debiting not reflecting all the consultants don't know they transfer me from one consultant to another.