Have received several calls on my cell phone from this number over many weeks that I let go to voicemail.  No messages have been left until today at 8:41 AM Pacific.  After four seconds of silence a booming voice said, "Hello, can I speak to Cesar Lopez?"  After four seconds of background call center noise, the voice became timid and tentative and said, "Hello?"  Another four to five seconds of background call center noise and they hung up.