How do i reboot/set my settings to default on XPeria Play

[BigCloud]

Sorry for a stupid question like this, im new at smartphones. I want to do this because for some reason no one can hear me when im calling or im getting a call, but mic still works on camera...

 

[Sam-SonyXperia]

There is not really any setting that would cause this issue. However given the nature of the problem it is more likely hardware related so it may come down to sending the handset in for assessment by a repair agent unfortunately.