Caller ID said San Francisco, CA. They called March 8th 2017 at 12:52pm. Didn't give my iPhone the option to Decline the call. Left no message.

Unknown caller. Did not leave message. Caller i.d. reads "Unavailable". If you do not identify yourself as a person or company via caller i.d. (not a caller i.d. of state or city) or you fail to leave a message, you are immediately added to my call blocking "reject call" list. BLOCKED!!!!  Next time you call your call will not even ring my phone. It will be rejected instantly. Later, dude.

called no message blocked

Spam!

As others stated - caller ID showed Private and no message was left.  SPAM