We stayed at the marriott grand dunes last month. We had 3 different reservation #'s i got the one night on the account. One reservation was from a timeshare tour promo so i wouldn't get the nights. But the 4 night stay i paid for didn't come up. So i contacted my timeshare rep to look into it. She did and they put the nights on kinda. They didn't give me all 4 nights. I had about 13 nights left to make gold again before they changed things now i have 16 nights. It looks like they took some nights from my visa card. I did not return anything.
So keep an eye on your accounts maybe print out every month to keep a record of how many nights you have so when this happens you have proof. I had just thrown away a paper i got in the mail saying how many i had also.