888-563-4111

Called my cell phone at 9:30am Pacific Time; I did not answer; they did not leave voice mail message.

Actually a legitimate call from My Secret Shop - a service that has you go to specific stores or service providers to review your experiences. They pay as well. Mine was for an Acura dealership and getting an oil change.

If you know what the number is why are you here?

It shows in a search of this number who the number belongs to, but scammers spoof legitimate numbers and this site is about who called, not who the number belongs to.
Looks to me you found the info you posted about in the search results and posted to pretend you got a call, why would you do that? Why say it was "My Secret Shop", when it is  actually iSecretShop?
I suspect troll.....

Called my 650 area code cell phone at 2:00pm Pacific Time; I did not answer; they did not leave a voice mail message.

I'm wrong, they did leave a voice mail message, my visual voice mail just decided not to show me I had a new VM until later.  The caller identified herself in the VM message as iSecretShop, with which I do have a business relationship.