well months down the line i am due in court in february if i cannot 'prove' i purchased the vehicle despite showing loan statements, bank forms showing purpose of loan, statements from witnesses etc. what to do next? any help or advice would be greatly accepted!

hello i brought a car from a friend of a good friend about 8 months ago. today i received a letter from carlyle finance in cardiff saying they are the owner as the person who i brought it from had no right to sell it. they have given me a questionaire to fill in too. am i in the same boat? i know the consumer rights act says something along the lines of that if you have innocently purchased a vehicle in a genuine capacity then you are deemed to have 'good title' to the vehicle? does anyone have any more info on this as i am a little worrled? thanks in advance