Don't feel bad about this. You are not alone. Many people are given impressions that things are a certain way, when they're not. The golden rule in timesharing is "If a salespersons lips are moving, they're lying." They can and do say anything to make a sale. It's all about their commission. At least you now know exactly what is what. That's a good thing.
The other good news is you now have only one timeshare to pass along to a new owner. It's a process to sell a timeshare, and you're in a good place to do that. Start by asking Massanutten to send you an Estoppel about your ownership. That's a fact sheet letter that describes what you own, so you can provide that information to a potential new owner. It will contain things like what week you can reserve, or whether it's a floating week, (meaning you can reserve any week within a certain range of weeks, or even any week of the year.) it will tell you the unit size you own (how many bedrooms), maintenance fees you're paying, whether there are any Special Assessments or taxes due, and any other pertinent information about things. A new owner will want to know that information.
Once you know exactly what you have to sell, there are several places on Tug to do that. Start by looking at the top of this Forum for a Sticky titled "How to Sell Your Timeshare." That will get you started.
Good luck!
Dave