No Internet since service upgrade in my neighborhood

On Monday I got a text that Xifnity would be doing upgrades in my area to improve service.  The Internet went out about 3 times for 10 minutes then came back up.  Although they didn't finish everything and stated they would be back Thursday the 8th to finish, everything was at least working.

 Last night, internet went out for about an hour but came back on.  This morning it went out at 7:30AM and stayed out until I came home and unplugged modem (my own personal Arris T25 I've been using for 2 years) and it started working again.  My Xg1v4 x1 box however wasn't working and multiple power cycles did not fix it.  Stupidly, I unplugged modem again to troubleshoot x1 box and now I can't get the modem to reconnect.  I get upstream/downstream but the Online light just flashes.  They are coming tomorrow to look at it and are blaming my modem as the problem.  It is not my modem causing the problem.  Anyone have any advice or should I just assume the technicians messed something up while doing the neighborhood upgrade.