Don't worry, you are NEVER charged for declined orders. Your bank or credit card issuer still shows those charges as pending until they receive final confirmation that those orders were in fact declined, which usually happens in the evening.
When you make a purchase online, your credit card is not actually charged at that moment. The card processor checks with your bank or credit card issuer to first make sure you have enough available credit to complete the purchase. At that time, your bank or credit card issuer places a hold, or pending charge, on the amount of the intended purchase against your card. The card processor then makes sure the other information you input (for instance, your address) is correct, and if all is well the transaction is processed. If not, such as if you enter an incorrect address, then the transaction is declined.
In either case, your bank or credit card issuer still only has the pending charge on your account. The transaction won't be finalized until the early evening when the card processor sends final confirmations for all of the day's transactions to the banks as explained above.
So, if you had 3 transactions declined and one accepted at 2:00PM, and then checked with your bank at 3:15PM, they would still show all 4 transactions on your account. That is because they won't know until later that evening that 3 were declined. Once they receive that information, those pending charges will be removed from your account.
Charges made after that day's transactions are confirmed, will be processed with the following day's charges.
This is NOT a situation unique with this website, but it is how virtually all online transactions are handled.
PLEASE NOTE: Some banks or credit card issuers can take 48 hours or longer before they remove pending charges.