714-551-6221

Caller ID said "Dynata".  It sounded like a robo call that wasn't ready yet (?).  No one was there anyway.  And I'm kicking myself for picking up.

Not a telemarketer.  Telemarketers sell goods and/or services.  Telephone survey company which you could have easily found out along with how to stop the calls.

Oh Look, it's me again.
Caller ID "DYNATA".  These are always silent calls.  There is never a message.  The caller ID has shown these numbers two other numbers as well: 714-486-0679 and 714-790-3424 and there may be many more.  Regardless of the callback number, this is what Wikipedia says about them:  Dynata is used to track online consumers' website history to look for and collect data about their purchasing behavior. The company also composes and proposes surveys to its users to get more accurate and clarified responses from broad-based consumers.
To opt out of their calls, you have to call them (seriously?!?!?) at 833-757-1746.  Or you can do what I do and ignore them.