I use the 3m-50 filtrete with the cloudbeam.com/our home spaces radio http://store.ourhomespaces.com/
The only app available is for the iPhone, no android or windows phone 8 app available.
As for the problem with the C wire, did you ever check for continuity, to make sure that the wire was not broke somewhere along the line? You can also use a external power source for these thermostats, that would plug in and then connect to the NEST.
Nest may send you out a new thermostat if the one you had did not work after making sure all wiring was properly connected at the furnace, and same at the thermostat. There are also some setup that you have to do on the thermostat, once you get it powered up, for type of furnace, ac/heat-pump, etc..