The whole idea was, you paid a deposit to secure some agreement, if you had a receipt showing what the agreement was, and what was the place of the deposit in the agreement, then there would be no dispute.
Never give money without getting something to show exactly what it was for?
Now, you can still ask the broker, but they will probably make up a receipt to reflect what they want it to show.
Get the idea? The oral agreement, unless you can prove that there was a definite promise and what it said, probably isn't worth much. Without an agreement (and any agreement is worthless if you cannot prove that it existed and what it said) they can probably change the details all they want.
But they have to answer to, what was the deposit for?
By the way, I don't know anything about MA law.