I loaned someone $10,000 a month ago. I gave them a certified check as a paper trail. They sold a house and have $ but not paying me back as agreed

I loaned someone $10,000 for a vehicle purchase in June . We agree when he sold his rental property that he would pay me back. I just checked the Redfin Real Estate site and he sold it for $190,000. I asked him for my money and he said he said no. I loaned him the money via a certified check from the bank. He has a new vehicle which he purchased before the home sold. What should I do?