Currently, when making purchases online or over the phone, businesses are allowed to make a "debit pre-authorization" where they place a hold on funds from your debit or credit card to make sure you have sufficient funds for the purchase. This hold usually happens in less than one minute, however if you cancel your order, it can take anywhere from 3-14 "business days" for the company to release the hold on those funds.
Any business that uses "debit pre-authorization" should be required to have appropriate procedures and or personnel available so that the release of the authorization can occur just a quickly as the authorization did. If they placed the hold in less than a minute, they should have to release the hold in less than one minute. Otherwise, they cannot pre-hold any money.