Who called from 2120000000

I got a call on my cell phone from this number. When I answered, the other end disconnected.

i picked up and it disconnected. i also tried calling the number and the recording said it was not in service any longer!

Got a call from this number but it disconnected before I could answer.  No message left.  Turned out to be someone that I knew calling me from a pay phone in Canada!

I got a call last night from this number. When I tried to call the number, it said the call can't go through

They left a message in Arabic and I tried to call them back to find out it was an invalid number.