Nest receiver not transmitting power to thermostat

[StaplesR]

My Nest thermostat 3rd Gen has worked perfectly for past 4 years. However, the thermostat no longer powers up (it’s connected to mains and not by battery), the issue is with the receiver that is connected to my boiler, it’s no longer transmitting power to the thermostat. 
The product is out of warranty and rather than completely replace it, I was hoping there is a simplistic solution?

Thanks

[Jenelyn_O]

Hi StaplesR,

Thanks for reaching out. I'm sorry for the delay. A few questions: in what country are you located? What do you pertain about the Nest Thermostat being connected to the main and not by the battery? Were you able to contact our support? If yes, could you please provide your case ID number? I'd like to take a closer look at it. 

Best,

Jenelyn