void bad buy contract option back to lease terms

[flori]

Trying to buy my leased car(nissan 2010) last Week I was told that all my high car payments (20) will not be deducted from my payoff. I got in panic and I signed paperwork to buy the car without reading the terms. The next days I went to the dealership trying to void the contract and go back to my lease terms. The finance person told me to wait since he is trying to contact the bank. he is going to call me. I have no contract in my hands. The sales manager told me it is no way to go back to my lease contract. I will be paying more than a cost to buy a new car. It is possible to cancel the contract? The dealership inflated the payoff adding more warranties, services,GAP, etc. I do not have an item by item cost included in the contract.