Recently passed Gran mothers telephone number linked to granson unknowingly.

I started a place of work, where instantly they gave me a phone (as you would expect) and at the initial stage. I was unaware that there was a direct number set up on these phone and just thought it was the global telephone number for the company of which a receptionist would put calls through to my extension. I never received direct calls. On a personal matter my grandmother passed away, and weeks after she died, I started getting calls direct (not through the receptionist). The calls were for my late grandmother, Mrs P Jarrett, (Note my surname Metcalf, hence, no connection there). The first few calls (perhaps, one a week) I ignored as was still secretly in grieving, but after a few months was starting to get annoyed with this repeatedly reminding me of my gran, and thought to investigate. We worked out that each phone (not to any ones knowledge), had a direct number installed at the time of my grandmothers passing. Each phone got assigned a number and without anyone knowing, I had been given my grans number after she died, what are the chances of this?