My contractor is threatening to lien over a bill that is less than 5 days old. 1- Our contract stipulates that if there are differences we must go to arbitration. He is bypassing that. 2- I am withholding funds because I paid in full for a specific part of the work that has not been completed. I have informed the contractor that I will pay my bill in full when he completes the unfinished work that has already been paid for. He refuses.