Sorry, sorry, sorry!
Nothing tests the limits of your marketing team's speed more than realizing that there was a mistake in the email that was just sent - whether it was a broken link, an invalid voucher code, or just a mess of foreign characters where text should be.
As I've highlighted previously, the best thing to do is to just admit the mistake and address it as quickly as possible. If you find yourself in this situation, you're in good company. For reference, here is what other brands have done to address their mistakes. (Click images to enlarge.)
Issues with foreign languages and characters
Note lastminute.com's issue with foreign characters in the subject line. To rectify this, they removed the quotation marks and replaced them with single quotes.
They also fixed the more egregious error of a missing apostrophe. The original email copy also came through as gobbledygook, but sending a corrected email as quickly as possible afterwards limits customer service issues. However, too many mistakes can lead to an issue with brand perception (not to mention pink slips for the QA team).
Citrix sent out an email German to its UK audience. The problem: the wrong database was loaded. Since the recipients should not have received the email to begin with, sending an updated email in the correct language would not have made sense. Their only option was to send this explanatory email.