Tried switching?

[myfirst]

Hi,
I recently got a D2G and the call quality was great, but two weeks later it went south.

I did everything from unchecking the voice privacy to taking the batteries out. Now, when I try to change it from EVRC to EVRC-B, it won't change?
I got on the menu, and changed the service options to EVRC-B, I can't find the "apply" anywhere. I hit the menu key at the bottom and nothing, phone doesn't reboot or anything. I tried to reset it myself too but nothing. Everytime I set it on EVRC-B, a few minutes later it will go back to EVRC.

I spent a few hours just trying to figure it out and no luck.
sorry, I can't find any answers to my problem.

Thanks for anyone that can help out!