Happened to me. I've been trying to redeem for Marriot points since January (twice). Each time the points would be put back in my account.
I sent them an email after the last redeposit (and right before the point increase) and they replied that they had an inventory problem. They also indicated that they would give my request priority.
Well, the points are now gone from my account (as of 6/26) and I haven't yet received the point certificates.
Time for another nasty-gram.
Mary