""My beloved thermomix is not working properly, the blades appear to be spinning but it's not actually mixing/chopping/grinding anything. The knead cycle doesn't show up on the display or work and the turbo button doesn't work""

I know this is long after the date you posted, however my TM did exactly the same including the knead cycle not showing up. I was lucky enough to borrow my sisters bowel and blade to test and compare in my TM. What I found was that the blade on mine had indeed come loose. When you hold the black base that fits into the section on the TM the blades themselves are NOT meant to turn independantly. When I tightened them VERY carefully with Multigrips on the top bulb of the metal blade, and using flat nosed pliers that I padded on the black plastic section on the bottom of the blades (so as not to dent the plastic portion) I was able to carefully tighten the blade. This was a last effort attempt for a long out of warrenty machine - of course if your under warrently, dont touch it just get onto your supplier/HO.

My TM now works again just like it should - I have it over 5 years and never had any problems before.

I dont baby my TM at all - I often slightly overload my bowel, dont hesitate to chop up frozen lumps of ginger, whole frozen bananas, refrigerated rock hard dates etc. and given this is my first glitch after 5 years of continual (almost daily use) I am more than happy with the performance and being able to to find a practical solution to my first problem.