If you have a signed contract with a stated amount you can put a lien on any business assets that they have. You can file a D&B report on their business credit

If you have a signed contract with a stated amount you can put a lien on any business assets that they have. You can file a D&B report on their business credit or you can file a complaint with the BBB. The last, while easy, is not that great unless they have a large consumer base.