If you only received 1 order confirmation email, your card was only charged once.
The other instances you may see in your bank account are pending transactions from failed checkout attempts in our shopping cart. Since you attempted to place the order but your request was rejected for invalid billing information or other reasons, the attempts will show as "pending" in your account. Depending on your bank or card issuing company, it can take anywhere from one business day to two full billing cycles for this pending charge to expire and no longer show in your account. For timing, contact your bank or card issuing company.