VW Fox 2010 1.2 not enough current for battery

Your charging system sounds normal. I suspect either your battery is dying or car’s electronics have a parasitic drain in one of the circuits when the car is turned off and parked. You will need to have someone check that with a suitable DC ammeter to find out if that is the case. I am afraid you wasted money on the alternator repair. Clamp on ammeters suitable for this testing are not cheap… https://www.omega.com/pptst/HHM-MA1500.h... but then again neither is wasting money on unneeded repair work. Sorry to deliver bad news. Good luck finding reliable shop to address the real problem. You should probably have that battery tested for capacity first before looking for a drain when car is parked.