Shoddy work done on Wendy house

This is the worst Wendy house construction I have encountered, No door frames, doors mounted directly onto studs, 6.5mm ceiling board not dry-walling used without studs on the walls. no fiber-tape used on joints 10mm "wet off saw" used in ship-lap style, corners exposed. no wall brandering used, ceiling board all bent Light fittings not mounted on brandering. No water piping done in walls. Electricity run to wendy from house on an extention cord, directly into the distribution board. levelling of wendy done on cinder bricks and planks Roof sheeting has gaps showing light through. Bathroom not installed, Contractor wanted a final payment but has not completed, contractor currently not answering calls