We had dealings with them a few years ago. They were useless when it came to the final details - though your problem is far more than that. Just make yourself a permanent pain in the ass for the foreman on site and write letters to head office; they need to get the message that you will not go away.
Have you moved in yet?
One bit of advice I got from a friend in the building game/racket was to always remember that the developer wants your money - and wants it badly. Everyday that you delay completion adds interest to the loans they took out against the development. We were due to move in two weeks before the builders holidays and had given notice to the landlord we were renting from. Sure enough the builders had done nothing on the snag list - lights in the wrong place, wallpaper that had bubbles and tears. So we just refused to complete - they threatened legal action so we said go ahead. The foreman said we would have to wait until after the hols; fine by us. What about your landlord, we've got covered. How nice of him to be so concerned about us!
The long and the short of it is, two weeks later everything was done - new wallpaper included.
Remember if you don't complete the foreman has to explain why to the developer. The buyer does have power, it's just that builders are very good a making you feel otherwise!