phone x-file

Someone : I suspect somebody is using my phone.
Me : How did you know? Redial showing unknown number?
Someone : Nope. My phone receiver stinks.
Me : *trying hard not to laugh*

Can you solve the mystery above? Just use 0.00001% of your brain. Guess who is the culprit behind the stinking phone receiver. By the way, that someone has her own cubicle.