I'm going to copy a post I made on another thread because it's relevant here as well...
Let me say up front that I completely, totally, 100% understand the stress and pain of not only having your vacation cancelled, but possibly losing the money you paid for your lodging. I don't want to minimize anyone's frustration or financial losses. I would be upset too.
I just looked at my most recent rental agreement from David's (sent to both parties before any payments are made) and it clearly states that the balance paid by the renter is non-refundable and that David's is not liable for operations changes by the resort (i.e., closures). The only condition I can see under which a refund is offered is if an action is taken by the member that results in the cancellation of the reservation and a comparable reservation can't be secured for the same dates. This would cover situations like members cancelling reservations, or DVC cancelling a member's reservations because they've defaulted on their mortgage or maintenance fees.
I think this would work against anyone trying to dispute a charge with their credit card company. If there's an agreement in place that the renter agreed to before sending funds, and that agreement has not been violated, I'm not sure what can the credit card company can do.
I'm not going to get into what I think David's should do; I don't know what they can do. That's their call. I do know that they're a reputable business with a very professional staff, and they will get back for you.
As for the wait for a response, I'll just say that every travel company on the planet is getting slammed right now. This isn't like contacting Disney or Expedia, who have hundreds or thousands of people manning the customer service line. It's a small-ish business getting contacted by every single customer with a reservation in the next few months, all at once. Give it a couple of days so they can dig through the avalanche of e-mail.