I got a new Sony Ericcson Xpera "Ray" about 2 years ago. Recently, I added my wife to my mobility account and she uses my old LG flip phone. When she sends me a text from the LG, my Sony reads it as "null". She can send normal texts to all other phones. The LG phone formerly had the phone number I now use on my Sony phone. Any thoughts? I've spent about 2 hours with Telus techies without any success.
Not sure what could cause that, but you could try to reset her phone to manufacturer's default settings under Menu>Settings>System>Security>Enter your lock code (by default it's the last 4 digits of your phone number)>Select Reset Defaults>Press OK. This will only reset the settings, not your contents and contacts. Once that's done, dial *22803, select option 1 then option 2, then wait a few seconds until you hear the operator say programming was successful and hang up.