580-262-4006

Received phone call. No message. Believe its spam

Do not know anyone at this number. Refused to answer. They left no message. I am on national No Call List at this number.
Blocked for future incoming.

I received a call on my cell at11:56 AM on 12/17/14. No voicemail was left.

Got a call from this 580-262-4006 (Oklahoma) number on my cell, no message and when calling it back from my cell, I got a message to 'call back from the number I received the call on'..... sheesh, no thanks.......

UPDATE:

Later I called again and got a live person who said he was with the 'National State Troopers Association' seeking money. Told him I was on the no call registry and he said it didn't apply to non-profits, do I told him I didn't apply to non-profits who 'cold-called' me and wasn't interested and hung up.