Not sure on the first 2 questions but would ask to see a receipt for the cambelt change -that way you will know its been done, alternatively check the service book to see if that item has been ticked off or call the dealer who did the servicing - they may have records to confirm if the belt was done.
On the scratches, if they are minor and not right through the paint, they should come out, a light cutting paste followed by polish might work.