My experience.
I used to drive Landrover 110's offroad for 70% of the time.
Because of the rough terain the rims were fitted with the highest quality tyres available and these were omni directional.
Following a regular service I tried to ploughed through a long section of axle deep mud, somewhere I would normally sail through, and instead came to a wheel spinning halt, a quick reverse got me out and I tried again, still no progress, out again and yes the wheels had been refitted with the treads the wrong way round.
Immediatly back to the service centre where it was discovered their new mechanic (this was in pre 'technician' days) was responsible for the mistake.
His punishment was to watched by the whole team while he pressure washed the whole of the underside, before being allowed to change the wheels around.
He then had to clear around 1m3 of mud off the washing area.
As for the OP
IMO the dealer is responsible 100%.
I would have insisted on a new wheel and tyre regardless of mileage, no messing.
If they had refused I would have gone direct to Germany with names, job titles and English (and German translation) statements of what was said between both parties.
Dealers are paid by the manufacturers, a decent sum for EVERY vehicle they sell inorder for them to recify any problems without incuring a loss, the sum was £300/car (Vauxhall) in the late '70's btw.
The dealers try and keep this money to increase their profits and why they have well developed avoidance techniques.
ALWAYS COMPLAIN BIGTIME.
After an annoying problem with a washing machine and the supplier refusing to replace the machine or compensate me, I told them to be at their showrooms on Sunday morning as I would be there with the machine AND the local tv and radio so they could watch me smash the machine to pieces with a sledgehammer!!!
Result - a new machine delivered that day plus financial compensation for the damaged clothes.
My motto:-
When a gentle push doesn't work, a hard kick in the family jewels usually results in a prompt solution.
