I am a general contractor for a home owner. We hired a subcontractor (plumber) who provided us with a bid proposal. He started the work but did not finish. He is now invoicing us for more than double the amount. we had to bring in another plumber to fix the problems and complete the work. We are not disputing we owe him something, but we see no grounds for him to more than doubling his price. Is he able to file a lien on the property based on this basic information? And our we able to back charge him for damage to the property and paying a new plumber to fix and complete this work?