Our shed got damaged by a storm and needed to be rebuilt. We got money from insurance and hired a construction company to come and rebuild the shed. They used wood and the floor in the old shed to build new one. This means their materials cost would be significantly less. There was no set price agreed upon and no written contract. We gave them a check for $8000 and said we’d give them the rest when it was finished. They came and put up the shed, but did not finish (windows, doors, leveling, moldings, etc.) They then sent us an invoice for $30,000. We told them we will not pay until job is complete and we don’t agree on $30,000. (We contacted other construction companies and got estimates of no more than $16,000 for the size of the shed). The contractor is now threatening to file a mechanics lien. Do we have a case?