Then there's nothing you can do.
If you owe it you have no defense and the HOA will get a judgment.
In NH a judgment is good for 20 years.
A judgment will allow the HOA to garnish your wages and levy your bank account.
A judgment could be recorded and become a lien on your home.
A judgment will trash your credit.
The longer it takes you to pay the judgment the bigger the debt will get with interest, costs, and lawyer fees.
Poor credit may impact your ability to get jobs and insurance.
Nothing good comes of losing in court.
I suggest you find the money and pay it off before the hearing in exchange for a dismissal in writing.