Thank you for reaching out to us and apologies for the inconvenience caused.
Test the receiver.
If you are currently on a call, the call will be ended when you test the receiver.
1. From the phone dialler, enter *#0283#.
2. Select LOOPBACK.
3. Select RCV_DualMic.
Say a few words as if you were on a call. If you hear your own voice, it's working correctly. Also ensure your software is updated
Then soft reset the device. Press and hold the power and volume down buttons for about 10 to 15 seconds (this will not erase your data, it is just to reboot the device)