Possible broken button on VCI-100 - need advice

Hi all

For a few months now the toggle snap button (tsi version 2.4/2.5) on my vci-100 has been unresponsive. The led light still goes on and off as I turn snap on and off manually with the mouse but the button itself does nothing when pressed. I havent bothered worrying about it until now, but as the tsi version 3 has just been released this button will now be more frequently used. So I'm wondering if there is a way to check what is wrong with the button, and if I need to replace it, what would be the best way? Where would I buy the part etc?

Cheers