Unfortunately, there is no quick fix by disputing with the bureaus. If you are above 50% of your credit limit, paying these down to 30% *might* get you the points you need, but you would need to pay these right away, and convince the cc companies to update your balance with the bureaus rather quickly.

Its been years since I was in Real Estate, but in Tx at least, all contracts called for the return of deposits if financing falls through.

While losing your dream home is disappointing, you might look at your contract again to clarify the loss of your deposit.