Have you transferred the insurance over into your name? If you have, give them a ring to find out what the procedure will be. If you haven't and the insurance is still in the sellers name (whether that be a business or person) then they will have to get it fixed through their insurance. If the damage happened in transit then it is the transit companies responsibility. If it happened before the transit company picked the vehicle up then you will also have to speak to them to get a statement of what they found, any pictures etc. They usually take pictures because if there is damage then they don't want to be held liable.