There are a number of reasons why your card has been charged. If you have your event setup to use your own merchant account or PayPal, then you are collecting service fees on our behalf. Every Monday we automatically collect all current service fees that you have collected the previous week.
There are a few other reasons why a charge might appear on your card. If you have recently purchased tickets, you will see a charge on your card. Another reason is if there were any refunds or chargebacks issued after the event was settled out. Since the funds are sent back to the customer, we must bill the card on file for reimbursement.