Welcome to the Forum.
my 09 card tray stopped working once, but played around prodding & pushing it & it started working again - hasn't failed since. Failing that the front of the button strip just levers off with a flat screwdriver (it's semi-flexible), be prepared to catch the hazard switch (which pops off because it's the only one fitted outside the strip) or go searching down the side of the center console for it. behind the strip there're a couple of little catch\clips in the top corners of the tray that need releasing before you can withdraw it.
I can't help with the HU because after 5 months of ownership I felt a need to upgrade - even though it wasn't too bad quality wise, it worked fine & looked like new! I like having more functionality. If it turns out to be a fix requiring payment, you might be better off either upgrading it or buying a secondhand one.