Contractors don't complete their job!!!

[Peace Lily]

Hi BP members,

It has been very frustrating working with my current contractors.  I am doing drywall, sheetrock, ceiling, build the wall, electrical wiring, sanding floor for the entire 2nd floor along with other jobs on the 1st and 3rd floor.  They kept delaying the job.  There are always excuses postponing the work and not meeting the deadline. I am always chasing them and they really lack of responses.  Should I just fire them or is there anyway to make them willing to finish by a certain date?  If I fire them and start looking for new contractors, it will cost more money and the completing date will be even pushed further. 

Does anyone have a reliable contractor recommendation for New Haven CT area? Some of the contractors I called from HomeAdvisor.com all booked out till October even November...  

Thank you!