u bought the car signing papers in hurry!!! without reading anything?? and u returned back without taking any papers with u??  why so childish n silly thing while buying such an expensive car??

now it's sure that they had that 17,500 amount in the sale bill, and u can do nothing.

The first thing would be getting the sales paperwork.  Go to the dealer again, ask for the sales paper and try to solve what's messing around.