How can I obtain a satisfaction of judgment where lien was already paid by cashiers check but recipient refuses to sign the proper form out of spite!

In Small Claims Case both parties were given something: The plaintiff was awarded $500 and the defendant was awarded return of goods. Defendant paid with Cashiers Check and has copies of front and back with Plaintiff's signature. It was cashed. Plaintiff was supposed to fill out and return satisfaction of judgement form but insists she wasn't paid and refuses. This is now a lien against my home and is on my credit record. I was forced to leave $1500 in escrow on the recent sale of my house, and was declined for a loan because of this $536 lien. Help!