Morning dude.
I had the same issue occur, when i owned my Audi A7. Minding my own business and boom, up comes the same message on the dash.
Lost all the even gears.
I got recommended 1 company in Essex, who could look and fix it. - Automatic Transmission Services Ltd, in Mersea, Essex.
T:- 01206 386 303
Long story short, it cost me £4500, for new clutch packs, and a host of other bits, but thankfully not the Mechatronics.
It was explained, that a transmission service hadn't been completed, though the service book had said it had, and the fluid had failed and fused bits together, having done over 70,000 miles!!!
Maybe give these guys a ring. They're very good.