Accident damaged car without declaration

On the 09 of September 2015 I have purchased a vehicle from Auto Pedigree. This car has been in an accident and they haven't declared this to me. I now want to cancel of the deal and they are not willing to do so and are saying they will give me another car however I do not want any dealings with then as they have **** to me the first time and I do not trust their words. The manager from auto pedigree has threatened me that if I do cancel of the deal my name will be garnished at the bank as it has been financed from the bank. I do not wish to have dealings with them and I no longer wish to continue my deal with them. Please do not fall for their words as they are ***** and wait to catch innocent people in to buying accident damaged cars without declaring that the car has been in an accident.