very common practice as they tend to oversell like flight tickets because there might be 5 people interested but only 2 can get loan approved. They will make all sort of excuses in this situation. I think the market practice refund double the amount of deposit but yr dev might not agree. Most prob will push those undesirable unsold units to you claiming discount given for the fiasco. Know that you can place a private caveat for a fee on your property when you place a deposit. That would avoid such problem in future. That would force the dev to deal with you rather than whoever first bank loan is approved.