First thing is your carrier doesn't matter. The reason for that is the beta version is BTU CSC code. So it's not related to any carrier. So if you're on 7.0 beta you should already receive an OTA (OVER THE AIR) update.
The only three reasons I might think of why you havent got an update yet are:
1) automatic updates switched off in your phone settings
2) Never checked for update manually
3) Rooted phone.
If you post more details about your phone CSC and device firmware version I might be able to tell you for what reason you havent received update yet.
Hope these screenshots help. I haven't rooted my phone. The only reason I know it's still in beta, is because every time my phone reboots, it says that the software is in beta!
Well. In UK the way you got beta was simple. You had a BTU version then you register and then the OTA update with beta was downloaded.
And that was the official way. By the way BETA version of 7.0 ( In UK) was ONLY available as BTU.