At the moment the voice chat only uses devices set as default in windows, please check that your microphone and headset are set as default devices in your windows sounds settings.
To set a default sound device:
Right click on the volume icon in the bottom right of the Windows task bar
Select 'Playback devices' for output devices (e.g. headphones) or 'Recording devices'
Right click on the device you would like to set as default and select 'Set as Default Device'
Make sure to hit 'Apply'
Repeat this process for both input and output devices.