Should I pay a contractor in full that hasn't done satisfactory work?

We hired a painting company to paint the exterior of our house. We signed an estimate and that was the only "contract" between us. The contractor never billed us until after the painting was completed. They did not re-glaze windows or do any caulking as listed in their estimate. They also did poor prep work and paint was splattered on the chimney brick, driveway and sidewalk. They came out and looked and said they would fix these issues but they have not shown twice now as scheduled. I would like to withhold payment but am afraid of a mechanics lien by doing so. I'm thinking it might be best to pay them in full and get pricing for what was not complete and/or damaged and then go to small claims to re-coop those costs. Would appreciate feedback. Thank you!