Hello Markbery2007,
a supermarket has the right to reject payment with too many coins, that means more than 50 coins - in normal times.
The problem now is, that the WHO recommended cashless payments, as there is still no final proof that Covid19 is not transmitted through coins and bank notes. Therefore some supermarkets refuse to accept cash at all.
I hope my answers were helpful and I’ll be very pleased if you contact me again with further questions. I'm a member of the mbeon-staff and I‘ll be glad to guide over a longer period of time. mbeon is an online advisory service for migrants via the mbeon-app, which you can download on your smartphone for free. You'll find me in the mbeon-app under my name „München, Frau Müller“ and get confidential one-to-one advice in a safe virtual room where nobody can read messages. For further information please visit ***.mbeon.de.
Download for Android: https://play.google.***/store/apps/details?id=de.zone35.mbeon
Download for iOS: https://apps.apple.***/de/app/mbeon-messengerberatung/id1408795643
Best regards
mbeon-Christine