Billa clerk cheating me 50€ cents from the change - Nussdorferstrasse 90,Vienna

I visited Billa on Nussdorferstrasse 90 and the clerk Kiinska cheated me the change of .50€ cents. The receipt shows the date May 27th, 2020, 14.57. It was 10€ banknote loss for the 50/100€ banknote changes and now I found the small changes cheated like .50€ cent patterns at Billas. The shops has the security cameras and only the Praterstern got automated payment machine for all the cashier process. Perhaps, Billa only needs such automated processing than the stealing clerks recruited in. I need to make the database of the cheating clerks and alarm beeping stores. Enough discrimination happened to me.