Realtor Committing Slander?

A month ago I put my house up for sale by owner. Within a week, a local realtor came to my door asking if I might be interested in listing my home with them. I said not at this time and they went on thier way. Two days ago I was contacted by a company that buys homes and they sent out a local realtor to ess my home. They chose the realtor that I turned down. The company contacted me this evening and told me that the realtor had told them this house should be torn down to the foundation and that he couldn't tell them it was worth anything because it needed so much work. Two years ago this home appraised for $55000. Since then I have replaced windows, put up new drywall, put down new flooring and I am currently in the process of putting up new siding. I was looking to get payoff for this home - $35000, and the realtor told the company it was no way worth that. The inside needs to be finished painted and mudded, but other than that, it is a huge home with a newer roof and many updates. This particular realtor didn't even look in all the rooms, nor did he check out the furnace, breaker box, or other major points of the home. Can I do anything about his slander?