A fellow by the profile name view was able change booking for the LHW $19.28 promotional rate for a 5-star property on Koh Samui. Although this is a different offer by a different company, it won't hurt to try to change booking or get a refund. Call or write Accor, the worse thing that they can tell you is "no"

http://www.flyertalk.com/forum/trip-...de-trip-2.html

The next morning I found a note under my door explaining that the BKK flights were still cancelled and I would be spending another night at SQs expense. The hotel was fully booked by this time, especially with Quantas and BA customers bound for Thailand, as they'd rerouted BKK flights to SIN. Talking with my dad, who was stuck in Bangkok, he thought there was no imminent chance of airport re-opening and advised me to look for alternative routings to get back to Europe. This meant I missed my stay at the Bo Phut in Koh Samui, the 5 star resort I had been lucky enough to book in LHWs 1928 promotion. Very unfortunate as I was looking forward to some days on the beach, so I informed them I would be unable to join them. The conditions of the offer explicitly stated no change of dates allowed, but they were more than happy to accommodate me later due to the exceptional circumstances. Well done.