Thanks for the comments guys. I did try to call Marriott; several times to the conference organizer at the hotel and finally to the 800 number where they promised to "look into it". Since I am calling ffrom ouside the US it is expensive to stay on hold for 20 mins at international rates........

I had elected for Marriott miles and the bonus for group organisers was in place at that time. SInce it was a school group there were no other individuals claiming credit for the rooms.

All of my communications seem to have been ignored. I suppose by now it is too far in the past for them to bother with it. After all, what is one customer to such a big organisation.