I have been gettingMANY calls from this number and 2 or 3 other numbers. I don't andwer the phone . Wait for a message. No message  -  no friend!

Oh yeah, I called the number from a landline and got a recording saying I had just dialed a number that isn't in use....

Usage of CPE (Customer Provided Equipment) means that the caller-ID information has been set by the caller.  Thus, they can call you, while they are showing a "not-in-service" number.  So, because the number is "unassigned", no telephone-company (Bell, Telus, Shaw, et cetera) can route the number back to them.

Just don't pick up, scam.