Guest
@Tobi25 According to your description, you first went to the SelfCheckout - it didn't work - then you packed everything together and went to a normal checkout and then paid in cash, for example.
If you showed Cumulus at both locations, then your Cumulus account contains 2 checkout slips with the same items paid for every minute at 2 locations, and Migros will certainly accept this evidence.
Without Cumulus, it's a case of testimony against testimony - I'm afraid there's not much you can do then = anonymous purchase - unless Migros can read out such cases anyway.