You look to your listing agreement and see what rights you have.
Regardless of the listing agreement, 2 rights you never have are that:
1) You can't file a Lis Pendens
2) You can't serve a motion for summary judgment in lieu of complaint (CPLR 3213) & must litigate the matter with a Summons and Complaint.
You may have to arbitrate pursuant to your listing agreement and you certainly should be mindful of Real Property Law 294-b, which permits you to file an affidavit of entitlement with the County Clerk and demand that your client deposits your claimed commission in the Clerk's office. Moreover, your client's failure to so deposit your commission will entitle you to costs and attorneys' fees in your subsequent litigation with the client.
Yet, no matter what you do, unfortunately, the Courts have uniformly stated that a real estate commission isn't entitled to a lien on real property pre-judgment. Maybe, its time to increase that lobbying.
Its time to get paid.