Bests & Worsts Reviews from Amazon

Bought this 1 year ago and thermostat has been great until just now. It is no longer sending enough voltage to the HVAC and the AC is no longer working. Had to have an HVAC tech come out to see what was wrong and they diagnosed and confirmed the issue is with the Nest (hooked up a different thermostat and it worked fine, also connected wires directly and system worked fine). Not sure if this is the result of a firmware upgrade or not. Trying to get some help from Nest support but have been on hold for several hours and have tried multiple times - they are useless. Amazon support was great though!