Originally Posted by
DFWFairy
... said they could not add my number on since I booked on a third party site..
What do the terms of their program say?
Rooms booked through third party online retailers, such as Expedia.com, Travelocity.com, Hotels.com, Booking.com, Priceline.com, Tripadvisor.com or any other 3rd party online/mobile travel portal (regardless of how the hotel is paid) are not eligible for Points or Elite night credit.
http://www.marriott.com/rewards/terms/earning.mi