Do not be alarmed, we have not double charged you. This recurring charge is a label some credit card companies use for charges that have an authentication token attached to the transaction. It is not in fact a recurring charge but a method to adjust an order without re-entering one's payment details. Transactions are not altered without your authorization. Please review your credit card statement to ensure you see only one transaction and rest assured that no other transactions will appear unless you purchase more tickets.
If you have further concerns about this, please contact firstname.lastname@example.org.