Sram Transmission derailleur possibly dead?

[Farisei]

I have a bike in with an unresponsive transmission derailleur. Customer said it was hit with a stick that went into the spokes.

There's no obvious damage other than wear and tear scuff marks. The battery is good and tested with the dropper. The shifter is good and working.

The button on the derailleur does nothing. Single click, double clicking and holding the button. no response, no servo buzz, no light.

I've followed the sram reset guides and still no joy.

Any tips?