Financing somewhat strangely expired

Hello, my grandpa has financed a used car directly from Renault. This is 74 and the vehicle costs 14000€. He gave his pension notice to the seller and he typed all the data into his computer. After 2 minutes the decision was made by the Renault Bank. He had to make countless signatures (very many). The seller copied everything and we could go. The vehicle is currently still on the yard of the dealer (HU etc. are still being made) As far as s o well, I have now read through the loan request and determined that in case of income instead of 1320€ (pension) stands for 1680€. The seller has done this on his own, my grandpa only gave his pension notice. The Renaultbank will want to know where the remaining 350€ are? The dealer is a Renault car dealer. Financing data: 14000€ to 48 months with a closing rate of 2000€. Letter goes to the bank after registration. Opa does not have to rent zah 300€ for the car. He wants to have the car and can’t explain why the dealer does it that way.