Hi there

There are a few things you can try before contacting Support (of which they will get you to do anyway)

1. Disconnect the BT box completely from the TV (lets remove a possibility)
2. Ensure that you have the latest firmware installed.  See : HERE for more details.
3. Perform a Factory Reset of the TV.  Instructions : HERE

If things still do not work after that, there is probably not much this forum can help you with.  Best to contact Sony Support : HERE

Let us know how you get on anyway - im curious to know

Cheers