Who the hell am I supposed to call about this issue with Nest? Despairing

[Yuapppp]

Had three !! Gas engineers out. All said the boiler is fine. Noticed that the heating seems to go off when there’s a power cut. However I’ve re set everything, the boiler, the nest system, everything. It’s all saying it’s working except the house is freezing cold. Who would fix this? I absolutely despise the system and hated it the moment we moved in!

sorry if you’ve already done it, but have you tried new batteries?

If your Nest Thermostat won't turn on, the batteries could have drained or there could be a power issue. If there's a power issue, your thermostat's battery will drain and it'll turn off Wi-Fi, the display and other features to preserve battery life.
support.google.com/googlenest/answer/9233319?hl=en-GB#zippy=%2Cnest-thermostat

There is always an override find it and see if it works.