redo needed for newly installed kitchen sink and drain line

Contractor sub (who evidently was not a plumber) installed my new single kitchen sink and garbage disposal. With water running, water fills to top of interior of garbage disposal and then disposal never full drains once water is turned off. Contractor installed Oatey vent but not a fix. Now says has to change drain line to go through the floor (we have crawl space where drain ties into main drain) or says he can remove the exterior siding panel and cut lower hole at back of cabinet wall to re-run the drain line into the wall and down to the crawl space. Have uploaded pics if helpful.