I think you'll find the Royals won't make any effort to sell your unit. But, it doesn't hurt to list it with them. They'll likely encourage you to sell it yourself. They won't refer you to an upfront fee company, unless maybe you get your resale info from a Royals bell hop. That said they do sell units. I think it takes someone to walk in, ask to see the resale list who is looking to supplement what they have or are looking for a low price. A combination of both would give you the best chance, ie lucky, but it happens.
There are a couple of individuals that have businesses renting & reselling Royal units, their experience doesn't match Denise's "belief". Personally I rent multiple weeks there every year, my experience never matches what Denise posts about Mexico, that said resales are very difficult at a price we'd like. Hopefully you don't have to sell now. If you can use it, rent it, trade it etc all the while listing it, with time you can improve your chances.
Maybe Denise would be so kind and list the Royal Hacienda units that have been given away. That'd be good information for you.