Hello first time home buyer,
It seems you are close to settlement and panicking. Make sure if you hire an attorney - they practice real estate law. Sit down with a real estate professional you can trust and figure out next course of action. One cannot really assist you on a forum like this without knowing all the facts.
You have to ask yourself, is it the house you want? Are you getting it at a fair price? Is the HOA one time contribution keeping you from buying your dream home? All said and done - like someone already said - the attorney fees may be way higher than that HOA contribution.
Your contract is always with the Broker not the agent - so if you have any issues with your agent, talk to the manager/broker of that office and they will assign another agent, and take the time to help you through your situation.
As for the HOA docs - they have to be delivered to the BUYER (not the representative - sorry Fran and Mark, Nick is right) - so you may still have an opportunity to walk and recover your deposit.