Called and hung up 2 mins ago.

Called 2 minutes ago.  One ring and hung up.

Called, 1 ring, hung up.

Called and hung up.

Got a call and called back to see if I could get a company name. Reward Redemption services. Claimed I had visited one of their affiliates. Press 2 to be added to their No Call listing. This is a cold call and it's how they get around some of the DONOTCALL lists. They don't technically answer and there is probably some kind of loophole they use because you have call them back to get any information.
It's probably a throw away number.