I know I'm replying to an old thread, but I'm having a similar problem on my LG Revere from a source with a number greater than 10 digits, but the message is similar to what you describe above, i.e., /BREW and a bunch of code. I discovered that my cell phone OS is BREW and wonder what the connection might be. I've tried everything but terminating my account to resolve this issue. I've blocked everything that can be blocked and the LG Revere is a basic phone. I just blocked data with the help of a support person on the phone and received two more of these rogue messages within the next 1/2 hour. It's enough to make a sane man cry.
What you need to do is either activate the old phone and delete any old email accounts that may have been set up on it then reactivate the new phone (Which if the old phone is an Alltel phone you will not be able to do) or call CS TECH SUPPORT. (Option 3 in the Menu tree) and explain you are getting OZ/Brew text messages. They know how to fix this.
Or send a Direct Message to MikeS_VZW here on this site with your name, phone number and such. He can fix it also.