Mystery Solved.... Well sort of...

I hear a phone ringing.
It’s not the ring of any of the office phones I’m used to hearing, but I know it’s a phone.
It has a high muffled pitch.
I’m the only person in the office today, am I going crazy?
No... There’s DEFINITELY a phone ringing....
I get up walk around the offices, nobodies phones are lighting up.
I walk to the vacant receptionist’s desk, there’s not even a phone there...
The phone is still ringing..
Is this place haunted??
I listen again and follow the sound.....
There’s nothing there, not even a desk....
The phone continues to ring........
I look up to the ceiling… No it can’t be......
Ring, ring, ring
I grab a chair and start climbing.....
I slowly lift the ceiling piece.........
Yep, there’s the ringing phone......
WHY THE HELL IS THERE A RINING PHONE IN THE CEILING?!