The owner of the goods left before taking payment
Question

                I bought some goods from a
      person on the basis that I would pay him for them afterwards. Then I travelled and when I
      came back, I found out that he had left, and I could not find out where he is now. I left
      my address with his friends, but he has never got in touch. What should I do?
Praise be to Allah.You have to ask the people who know him and
    make the effort to find out where he is, then send the money to him, or else go and see
    him and give him what is due to him, because the Prophet 
 (peace and blessings of Allaah
    be upon him) said: “Every Muslim is sacred to another Muslim in his blood, his wealth
    and his honour.” It is not permissible for you to take the matter lightly. If you are
    unable to find him, then give the money in charity on his behalf, with the intention of
    repaying him too. If you then find him, then give him the choice between getting what is
    owed to him, in which case you will have the reward of giving in charity, or accepting the
    fact that you gave it in charity, in which case the reward will be his. Allaah says
    (interpretation of the meaning):
“So keep your duty to Allaah and fear Him as much as
    you can” [al-Taghaabun 64:16]
“Allaah burdens not a person beyond his scope”
    [al-Baqarah 2:286]
Shaykh Ibn Baaz (may Allaah have mercy on him).