Looking for advice on the following issue:

We've been working with a regional broker for 6 months and have preformed over $100k in PP services. Last month, we were informed, after they missed the scheduled payment, that they would not only be paying late, but that the check would be for half of the amount owed.

Then the check bounced. At which time we informed them that we would not accept any work orders until they resolved their financial issues.

The check has now cleared, but we are still owed $20,000. They have told us that the remaining payment is on hold. All of the work orders were from BAC, were completed correctly, and processed correctly.

I am looking for advice from anyone who has encountered a similar situation. Do I file a lawsuit in my state or theirs? Do I place liens on the properties (we do not have a "no lien" agreement with this company)? Do I seek reimbursment from BAC?

Any advice is greatly appreciated.

If you don't have a no lien agreement with them, then I would contact the bank and let them know that you are putting a lien on the property. That may get them to force the regional to pay you. But be careful in some areas you only have a certain amount of time to lien the property.
Also, if they owe you that much and are being crappy about it, send them to collections (if for nothing else, it would give you some satisfaction). Also it will put a mark on their company.