We have also received calls from this particular number.  It also shows up on our Caller ID as "INTERNATIONAL."  They didn't leave a message either.  When we tried calling the number back, there was a recording, with no company name or ID, which said an operator "will be with you shortly."

Only one call recently with the name INTERNATIONAL on my Caller ID unit-No message left.

no message call back says nothing btu an operator will be with you shortly and my number is not listed private number