Once you cancel, you will no longer be charged, but you are still responsible for charges that have already incurred in the current billing cycle. For instance, if your charge date is the 10th and you cancel on the 20th, you will no longer be charged but are still responsible for the current month's charges. In order to be fair to everyone, no exceptions will be made.
If you sign up for Vendor or the Week or Product of the Week, you have up to 14 days before the Listing Week to cancel the listing and receive a full refund. For instance, if you paid for the listing on Mar 1st, but your listing week starts on April 15th, you have up until April 1st to cancel and receive a refund. The new listing week will always start on Sunday and end on Saturday.
Services can be canceled at any time by logging in and clicking on the Cancel Service link found under the "Profile" section.