This one definitely needs to be addressed by your "real estate qualified" attorney.
While the numbers, credits, etc. can change on or just before settlment, they must:
1. Be reported accurately on the HUD1
2. Meet all the requirements of the law, FHA, agreement of sale, etc.
There are limits for:
1. The amount of gifts, credits, etc. that the buyer can receive from any party
2. There is a minimum amount of "cash" the buyer needs to supply (Lender specified)
And there may be more, but these are the first that come to mind.
Have your attorney review all of this and if you get a chance, let us know how you make out.
Since you are coming to the realization that you did not fully understand the changes thrown
at you during settlement, it seems pretty clear, it shouldn't have closed.