[iMore Question]

i can get the call but I can't hear it ring

[Tartarus]

Did you check the mute switch?

[SwitchBeach]

What phone?

In addition to the Mute switch, have you checked the "Do Not Disturb" function to make sure it is not on?
Have you checked the volume switches to make sure the volume is up?
Have you tried a hard reboot?

[Rob Phillips]

If all of the previous recommendations still don't fix your problem contact Apple Support or bring your iPhone into an Apple Store.