We are building an office as a commercial property and our contractor has decided to add multiple costs to the final bill that were NOT approved change orders (cost to take out trash and accept deliveries). Thus, we have not agreed on the final price. He is completing the punch list and now threatening to file a lien on the property. We said we would pay him 98% of total job cost with the 2% retainage fee but need written agreement on price and a release of liens form. He has not agreed nor given a release of liens form. Thus far we have paid about 75% of the total project. Can he file a lien on the property and how can we prevent that. We are happily willing to pay but want documentation that he and his subs will not file a lien.