We did get our deposit back from Pulte, but we had signed an addendum as part of an incentive where they would pay $6k of our closing costs if we used their mortgage company. In the addendum it was worded two ways - one sentence said if they didn't approve us within 30 days, the contract was canceled and the deposit was refunded. The other said that after 30 days the deposit was non-refundable. Confusing, to say the least. They ended up not approving us (we weren't able to sell our current home, so they wouldn't approve us with two mortgage payments, which made sense), but they gave us heartburn over the deposit.
After several months of trying to get them to call me back and admit that they didn't approve me without receiving any cooperation or even a phone call back, we found a lawyer through a friend that was willing to take on our case on a contingency basis - we don't win, we don't pay, in other words. He sent a letter demanding our deposit, and of course, they stonewalled us. He then asked them to start the arbitration process as described in the contract, and they basically told him to skip arbitration and go ahead and sue - in other words, they were "calling our bluff" by not thinking we'd want to go through the cost of a lawsuit.
We filed suit against them in January, at which time they had 20 days to respond or face a summary judgement. After 18 days, they called our lawyer and said they would refund us in full.
Summary - they won't work with you until you actually file suit with them, but we had the special language in that addendum that said they would refund us if we weren't approved. Stay away from Pulte Homes and Pulte Mortgage - it was a hard lesson to learn, and luckily our situation worked itself out, but I've heard stories from other folks here that went either way.