ASR Not Working After Instrument Change?

I had the instrument cluster replaced in my A6 (profile) a week ago.
auf Garantie getauscht bekommen (wg. FIS Display).
(A Recaro seat was also installed (including deactivation of the side airbag), and the cold start behavior was improved (pump adjustment).)

Today, for the first time, I noticed while it was snowing that the ASR (Anti-Slip Regulation) wasn't working.
The wheels spin freely, and the switch in the center console has no effect.
The warning light for the ASR (Anti-Slip Regulation) system in the car is either not illuminated or is flashing.
ABS is working.
ASR worked after the purchase in November, I am absolutely certain of that.

'Visited the friendly service center, no error codes found. Should schedule an appointment for a check-up.'
'But they don't want to hear anything about warranties or liability for defects.'
I'm afraid they're trying to sell me a new control unit (expensive, right?).

Did they cut corners when they replaced the combination unit, or could that be the cause of the problem?
or is there another explanation? I find the temporal connection quite striking.

Thank you, goodbye, Thomas.

Okay, the ASR (Anti-Slip Regulation) is not a wear item, so the dealer should... (the sentence is incomplete).
The warranty is valid until 05/11, unless the seller explicitly stated a one-year warranty, in which case they are still liable until 04/11.
He can't get out of that either.
So, bring him the car and have it repaired for free.

I'm back with the friendly mechanic.

They forgot to install an indicator light during the combination switch replacement.
*shakes head*