Earbuds may be non-compatible with the phone. That happens, I had a pair of beats that would cause my laptop to crash because of the way the controls were wired on the beats. The phone is not recognizing the earbuds. If a second pair exhibits the same thing, it may be the phone has a bad earbud sensor.
I tried the Apple earbuds and they work. The only thing is that I have small ears and they hurt my ears. The one's I got from walmart are fine in my ears but wont work with my iphone 5C.