I get text messages all the time from people who transpose the number with my RC number. The first one I got, I called the girl, and she indeed typed in my number thinking it was her boyfriend - it was off by one digit. Her message was very colorful - which is why I was inclined to call. Now, I just ignore them!!
What was happening to me a couple of times, in this case receiving an email with the message, because I configured the extension, first I put my own email and then I replaced with the owner of the extension, but when you update the contact info, the notification email is not updated at the same time, it needs to be done manually..