You are not thinking this through...

There is no benefit to calling now. Calling now either means accepting the no cancelation policy once it's explained or canceling the reservation, neither of which the OP wants to do. Not calling now gives him the chance to have that conversation if he wants to cancel later. Having the conversation now really means forfeiting his ability to cancel later.

What possible benefit could there be to calling now?

And I called BOTH Marriott and the property to make sure my card was not charged, as it was my work card, not my personal card. Both sources gave the same answer. The 800# canceled the reservation and the hotel confirmed it had been canceled.