Date Time Cancelling a car contract Buying a car can be a big expense, so it’s worth knowing that after signing on the dotted line there are costs you could be liable to pay if you change your mind or are unable to go through with the deal. Under the Motor Vehicle Dealers Act, a dealer is allowed to charge up to a maximum of 15 per cent of the contract’s value as ‘pre-estimated liquidated damages’. The actual amount should represent the true cost of the deal falling through to the business. Unfortunately though, it appears that sometimes this maximum rate is being used as a ‘flat rate’ in some sections of the industry.