Welcome to the Audi Owners Club !
Good to have you onboard.
Hello Gabriel,
Sorry to hear of the issues with the car. If this were mine, I would be tempted not to automatically accept that the battery (and alternator) or ‘OK’., and I would want to know:-
(1) By what means did they test the battery, and what were the results.
(2) I would be driving the car to Halfords and getting them to test the battery’s % efficiency.
Only when you have proof positive from both sources, would I be prepared to move on to investigate the more complicated possibilities.
Perhaps you could let us know how you get on.
Kind regards,
Gareth.