How to find who called with no callback number?

[AC Question]

I have a Samsung S4 Active and unfortunately I do NOT have great service where I work. Lately I have noticed that when someone calls my phone, it will go straight to voicemail. But how can I call back when it doesn't even show the number and they didn't leave a callback number?

 

[B. Diddy]

Welcome to Android Central! It should still be in the Recent Calls log--nothing shows up there? And you're sure these aren't "Unknown Number" calls, from callers who have Caller ID Blocking turned on?