Very disappointing service fro Wesbank

First time dealing with Wesbank and all went great. Second time trying to get finance with them I get pre-approval online and sent the ref number to the dealership. The F & I at the dealership who works for Wesbank starts giving me different figures on the finance. She says my balloon payment on my app is 40% and the bank will only approve 35%. My app says 30% is the max as its a pre-owned vehicle. Her monthly repayments were higher to than what is on my application. I called Wesbank to find out what is going on and 2 customer care consultants & 1 marketing person later, I still don't know what is going on and they cannot help me. I've had to ask the GM manager of the dealership to try sort it out. He to says it doesn't make sense