HEY HEY YOU YOU

I've been in a pretty shitty and depressed mood lately, but I figured I'd post this anecdote seeing as it's the greatest mystery of my day. I work in an office, and no one but me here is under the age of like... 35 or 40. Somehow though I still hear someones phone go off every other day with an Avril Lavigne "Girlfriend" ringtone. WHO IS IT?