Kansas...I had wondered it this ever got resolved. Your situation was different than mine cause you use the Cox voice mail as primary. If the pickup ring time was less than that set on the phone's answering machine, I would expect Cox Phone history would show the voice mail...however, I would not think the phones voice indicator to post the call message left on Cox mail.
So, if the phone message pickup is greater than the Cox voice pickup rings, you should never have any indicator or actual message on the phones voice. You could check the Cox call history for the times when messages of stored (120 days), looking for any conflict where 2 voice messages are left, one on each recorder. In my case, I was talking on the phone so my phone answer machine could not pick up, so the caller got transferred to the Cox voice mail. The call history may be something you could investigate next time.
When Cox voice mail is primary, is there any indicator that a message was left...like an App or maybe a blinking lite indicator on the phone. Curious about your exact situation.
