Sorry to hear that they're being crappy to you about your rebooting GNex.

If it were me, I'd ask for a manager (which you may have already done) and tell them you're switching carriers if you can get this fixed. Internet is nice but if you can get/make calls on the thing, that's a big inconvenience.

Alternatively you could call and ask for a customer retention rep. They might ship you a new one.