It costs nothing to call customer service.

My Nest thermostat is about 3 years old now, and it stopped connecting to the Wifi. Called Nest customer service, the rep. ran me through the same trouble shooting steps as what was on their website. Problem still didn't resolve. I asked him what is the best way to get a new nest. He put me on hold for a couple a mins and sent me an email asking for my mailing address, and I now have a new Nest Thermostat on its way.

Moral of the story: I was ready to lay down some money (~$200) for a new Nest, and a call to customer service saved me $200 even though the product is out of warranty.