My former employee (unbeknownst to me as company owner) engaged a plumber of mine on a residential remodel project. The general contractor has a contract with a homeowner. They are claiming that my plumbing company was acting as a subcontractor - although there was no contract with my company, no bid/proposal, and no statement of work. In the process, my plumber had a leak causing damage to the homeowner. The contractor and the owner now refuse to pay my invoice, demand damages to the property payment and want information on my liability insurance to make a claim. I am concerned because I was not aware of this job - it simply was not on my books. What are my options?