Oh, you are in BKK now? Head up to level 6 before security and pop into the ticketing office there - they are very switched on so if they can't do it, then you know it's a problem with the ticket you were sold rather than incompetent ticketing agents on the phone!

There is also a bit of a rip-off Chang massage next to the Concourse E/F/G junction on the shops level near the lounge if you don't have time for one in town!