German phrase
Bitte sperren Sie ~.
Meaning
Please block ___
When to use it
A polite request to block. Common for lost or compromised cards.
Example dialogue
Bitte sperren Sie meine Kreditkarte.
Please block my credit card.
Selbstverständlich, ich sperre sie sofort. Wie lautet Ihre Kartennummer?
Certainly, I will block it immediately. What is your card number?