Motorland failed to disclose motor being changed

On 1.12.16 I purchased a 2013 Fiesta from Motorland which I was told never had any problems, and was still under factory warranty. 3 days later I started having problems and they haven't ended. First the aircon was not blowing properly, I checked the service history to find it had missed its service by 7 months, meaning the warranty was voided.They then kindly booked it for the final FREE service at ECM. The num plate supp**** by them was missing a letter, the a/con pump is noisy, the steering column is knocking, the brakes were worn and they did not allow the Ford dealer to fix, they rebooked it without consulting me first to have them done at their workshop and then failed to fit the brand I requested, instead fitting a cheap brand. The vehicle has a shake at high speed(not wheel balancing).The car jumps out of reverse often. After many calls and some emails , and then some more calls, I got no help. I then threatened to cancel the sale and asked why the warranty was taking so log to reinstate.Then I received a letter stating the motor had seized and been changed which was never disclosed to us. Motorland says we should be happy it has a new motor and refuses to cancel the sale.