I received a demand letter from a craigslist buyer whom I sold a car to recently asking for repair money. I will make the story short as possible. I sold a car on CL, buyer came, inspected, test drove it, and paid for it. 5 minutes down the road buyer calls saying check light engine is on and wants to get a diagnostic test down at auto store and get back to us. After buyer text us saying it was to do with plugs and valves, we offered him refund for return of the car, buyer says they like car, papers signed already, and their fault for not further inspecting. Thought that was end of it, buyer calls again the next day and says check light flashing, being suspicious of his claim but since our first time selling car on CL, we offered refund again if buyer brought car back that same day because we were within our comfort zone of refunding him and taking car back since it was within 24 hours after sales. Buyer agrees to bring cars back, but said he would bring back in evening. We agreed. However, buyer flakes out and does not bring car back instead says that he had someone look at car and brought up new issues and that he wanted to keep car longer until looked at. We become uncomfortable and tell buyer that refund is off since car is not returned. We ceased all communications from there. We finally receive demand letter from buyer saying they will sue us for misrepresentation of the car and that we took advantage of them. They make claims that we monkeyed with the car before sales to make it good enough to sale, however, that is false. We disclosed everything about car to buyer before sales, car was fine and buyer had chance to test drive and inspect car. Buyer now says he has proof of receipts from his mechanic and cost for repair and wants us to deal with it. We feel we are not obligated to pay him a penny because the issues of the car occurred in his possession, and had no knowledge of those issues prior to the sale nor witness it. We offered him refund twice for return of car, but he failed to do so. My question is should I seek legal advise at this time, though we have not been served. This is my first time being in a situation so I have been overwhelm by it but I like to know how I can respond back to the demand letter properly and if seeking legal advice is good at this point to help me prepare in case we do go to small court claims. Any advice is appreciated. Thank you all for your time.