carmencam, a really good way to get them off your back is to tell them you're married but traveling without your spouse. That's like holy water to a vampire
I remember several years ago a thread on Flyertalk about Marriott timeshare presentations and how they were non-pressurised, informative and if at the end you said a firm "no" you'd be in and out after around the hour stated with the points crediting to your account a few days later.
Alas since being spun-off it would appear the MVC that carries Marriotts name and reputation is now no better than every other scamming high pressure timeshare sales outfit out there. That's a pity.