Driveway damaged during AT&T dig

My driveway was damage when AT&T was installing lines in my residential complex. I have already called the claims number, reported what happened, and sent an email with pictures and a video to the address given. Today I spoke to Denise Brown, a claims handler with "Sedgwick Claims Management", who is supposed to handle my claim, and she says AT&T has no responsibility over that, and that I need to contact MasTec, the contractor hired by AT&T in charge of that. The problem is, we really already tried that.

When they were working, they blocked our driveway for weeks with a machine and a huge pile of sand and rubble, and then for more time when trying to put it back to how it was, unsuccessfully. We told them it was unacceptable how they left it and they attempted to fix it two more times, unsuccessfully again. The pressure of the cars and the rain makes the pavers rise up and it's just a mess. We have to constantly put them back in and organize them. I have pictures which I already send in the email. Basically calling MasTec again is a waste of time, they'll come back with the same people and do a bad job again.

Why can't AT&T help me here and do they really have zero responsibility here? Does the party who hires a contractor to do a job have no responsibility whatsoever over damage said contractor causes? Can't AT&T go after MasTec? 

Thanks to anyone who can give my any info on this matter.