Check and see that the microphone is not being blocked by any particles or obstructions.

Check and see if the microphone are held at the adequate distance for it to be able to pick up the voice.

Check if the microphone was not exposed to any hazards like direct sunlight or fire, water, or dipped in any liquid.

Check to see if the mic hole is not clogged with dirt or sweat. If so, clean it with a cotton swab dipped in alcohol and gently blow dry it from a distance.

Check to see if the device has been properly connected (i.e., the Type-C connector is properly inserted).

Check if there is any loose wiring.

Check if the device was not subjected to any mishandling, broken wires, or exposed to direct sunlight or hazards like fire.

Check if the controls do not work when connected to another device.

Check if the media player being used supports such controls (Note: In-built controls may vary for different phone models).

Check if the controls do not function on call or with other media players.

Check if the controls have been physically damaged or exposed to any hazards.

Check if the connected device does not have any equalizer settings applied.

Check if the distortion or quality lowers at all volumes or only at high volumes.

Check using different media players and different devices.

Check to see if the earbuds have ear wax accumulated; if so, clean it with cotton swab and alcohol and gently blow dry it from a distance.

Check if the connected device does not have any equalizer settings applied.

Check using different media players and different devices and whether the volume change happens on all devices or only on specific ones.

Next Track: While playing music, press the MFB 2 times.

Previous Track: While playing music, press the MFB 3 times.

Answer Calls: Short press the MFB 1 time.

End Calls: Press and hold the MFB for 1 second to end an ongoing call.

Reject Calls: Press and hold the MFB for 1 second in the call ring status to reject the call.