In the process of having a pier construction . Already paid $3,000 when signed , $7,000 to start . Next 50 ft completed , another $7,000 . We have had 150 ft. completed of the 475 ft. During a negotiation for a change order , the first , over the phone , the Contractor agreed to extend the pier out to the original footprint and install to mooring pilings for an additional $2000.00 . He had previously included a 50 ft. walkway through the marsh for free . I stated we would wave the for free and he agreed to build it for $700.00 materials and labor . In the change order he had not included the mooring pilings and shortened the walkway to 10-12 ft. long for the $700.00 . After he attempted to shout me down over the phone and threatened to walk off the job , I declined to talk with him any further and ended the call . Then he pulled the crew off the the job . What should be my next move ?