Got a call from this number today (5/10/2017) at around 11 AM. Caller ID showed up as "NOT IN USE 1-909-245-8041". With a CID like that ("NOT IN USE"), I definitely let it roll thru to voice mail. Whoever it was they didn't bother to leave any message. Checked the area code-prefix (909-245), and found it listed as being a landline in Long Beach, California. A few hours later, I tried calling the number back (using *67 to block my own CID). My call got picked up on the first ring with some hold music playing. Then I got the following recorded message:
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"Your call is very important to us.
Please stay on the line and you will be transferred to the next available agent."
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I stayed on the line for maybe 30 seconds listening to more hold music. Then I hung up. There was never any identification or indication given as to a company or organization name. Added this number to my phone's Call Block List to stop any future calls from this number.