Well if you have TEP and go into a store and it is broke enough to be completely unable to make calls, they are supposed to fix it or replace it on the spot with the same or comparable model, new or refurb.
But if it's broke but can make calls they are supposed to get a replacement shipped to you. This was what a corporate guy was saying said over on buzzaboutwireless.
In real life it is basically up to the manager of the store, but a lot of people have been having success at stores.
If I was you I would call ask to get connected to "Account Services" they can upgrade you, just complain about your months of struggling with the 6700 bugs and now this (I love my 6700 too by the way, just saying that bad stuff
)