Space between concrete slab and ground- Do we need to repour?

This. ^^^^^ Look at your estimate and see what it says before you call your contractor. You need fill dirt brought in and graded gradually away from your slab. Unless the contractor said he would bring in fill and regrade your landscape, I would think that this falls into your lap. One commenter said it should have been leveled, no it requires filling not leveling. The contractor gave you a level slab so now you as the homeowner need to bring your landscaping up to match it. The only other way he could have done it, would have been to remove dirt and give you a sloped (decreasing grade away from garage door) slab. But most people prefer a level slab. Whatever happens needs to happen before someone drives on the corner which would break it off.