Is the slope not even addressed in the notes? There must be something. It's odd to me, living here in California where everything seems to be spelled out, to continue to hear about places where the permit is basically for the garage and the contractor seems to be responsible for determining how it is built. There is another similar thread going right now for a garage where the foundation retaining wall is failing. That one seems to be working out in the owner's favor. If you have a local planning department or Dept of Building and Safety, etc., I might call (or go) and see if I could talk to someone and get an official comment as to whether this construction falls within the range of what they consider acceptable or normal. In other words, you need to determine, one way or another, whether you have any recourse with the contractor. At the very least I'm assuming there is an issue with the garage door. If you reach an end, having exhausted all your other options, you most likely could pour a self leveling slurry over the existing floor then cut the driveway back from the opening and repour to the new floor level. The slurry should bond well as long as you have kept the existing slab fairly clean and free of oil, etc.
