Who called from 2894445208

I have been getting calls from this number off and on for a little more then a week. I don't normally answer the phone if I don't recognizes the phone number. Well today I did answer, I said hello and nothing, hello again still nothing. So I said goodbye and hung up. I called the number back and a recording said the number hasn't been assigned yet. How does an unassigned  phone number make a phone call?

I got 44 calls coming from this number.

Me toooooo
many calls mostly on the same day.... like if i get a call from this number on a specific day i get more than 1...
and i call back and it also says it hasnt been assigned... how annoying!!!

I blocked the number using the blocking function on my home phone, see if you have one ;) !

We are in Mississauga, do not call list.

We are also getting phone calls from the number  289-444-5208 - they never leave messages.

Who are they and why do they call us?