Why can't I hear people on calls?

[Hannah Myers1]

I took the case on and off. I can use headphones to hear. I can play music or hear on speaker, but I can't hear when calling. I need help. Thank you

 

[B. Diddy]

Welcome to Android Central! When you unplug your headphones, does the headphone icon remain in the status bar? If so, then something is wrong with the jack, which thinks the headphones are still plugged in.