Probably a scam.
I used to work for the Denver MLS, and Timeshare was one of the property types a Realtor could choose to list a property. I only saw a few listed. This was back in the mid-1990's. I think most Realtors would see this as a waste of time and effort to sell timeshares, but I also know that there are companies that specialize in timeshare sales that are legitimate and are worthy of the time in listing and buying.
Disney, Westin, Hilton, Marriott, etc, are all great products that are sold through real estate brokers. My favorites are sellingtimeshares.net and advantagevacation.com I have only purchased through advantagevacation.com but have perused the listings on other sites.
The salespeople need to be on top of things and not ignore messages and questions, as though we aren't worthy of their time. That is what I got from sellingtimeshares.net's Samuel Rodriguez. I stopped taking that guy seriously. Seth Nock was great but you cannot get him on the phone.
If you have something worthy to sell and are willing to take a very low price for it compared to developer price, those are places to contact. But if you have a timeshare not even worth the broker fee, you won't be able to sell it for much. Wyndham points, Shell, legacy timeshares (older fixed week and floating weeks/units) are not worth much at all.