Most of the time this is not a problem. However, if the car dealer cannot find someone to buy your purchase contract, it can cancel the purchase contract. But, the car dealer must notify you within 10 days of the date on the purchase contract. If it does not, then the purchase is final and cannot be cancelled.f you buy a car that is financed through the dealership, the dealer CAN cancel the contract, but only if it notifies you within 10 days of the date on the purchase contract.