Which button are you using to try and change the clock?
You use the one on the steering wheel to flick through last calls, media, etc etc until you come to settings if I remember?
If you use the menu button on the indicator stick, this is for different options.
The micro-switch in for the menu button can fail. If it feels spongy, then it's most likely gone.
There are a few suggestions on this forum (contact cleaner, through to opening it up and soldering another one in), but it could be a case of having to buy a 2nd hand stalk set, which are rare as hens teeth (more so with a sw version, as I found out).
Try the other suggestions first, before you start worrying about it being broken, though.