Looking for the rightful owner and returning the right or giving the right in charity on behalf of the owner

Q: In 1394 A.H. I bought a car for 9,000 Riyals in installments. I did not know a great deal about the person who sold me the car even though he used to know my address. However, because I was dismissed from my work and I moved from Riyadh to the Western Region; I stopped contacting him and he also does not contact me. I do not know his full name or address. Nevertheless, I would like to pay off the debt I owe to him. What should I do?

A: You have to look for the person to whom you owe the money. You can do this by advertising in newspapers or by asking anyone you think might know him among the people of his city. If after doing so you still can not find him, you must give the sum of money in Sadaqah (voluntary charity) or to a charitable project on his behalf. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions. (Part No. 14; Page No. 73)