If the device is still under warranty, then I would contact the manufacturer. If not, then you would either need to to take it to a tech to see if it is possible to repair/replace the microphone, or get an external mic.
If the device is still under warranty, then I would contact the manufacturer. If not, then you would either need to to take it to a tech to see if it is possible to repair/replace the microphone, or get an external mic.