JJ,

Was the contractor supposed to do all of the work involved in this
driveway or just pour the concrete? You mention not using the driveway
until it cured but not how the curing was done or who was responsible for
this. I'd guess based on what little info you provide that the driveway was
not properly cured or the ground under the driveway wasn't prepped, or the
wrong concrete was used. It needs to be completely redone. I'd suggest that
you get the contractor's insurance info and look for another contractor
unless you were doing most of the work yourself.

Dave M.