It is rare, but an auction can be cancelled after it has closed, and in those cases the domain will be returned to the registrar.
While this seldom happens, a rare set of circumstances may necessitate a domain auction to close early or be removed from your account. If a domain is removed from your account, you will receive full credit for all auction fees paid for the domain. NameJet management views this action very seriously and does not exercise this option lightly.
Per the NameJet Agreement, Section 3.4 in part:
You also agree that NameJet shall have the right in its sole discretion to suspend or cancel any auction (Public or Private) prior to commencement of, during, or after completion of, the auction.