After submitting B3, it is recommended to wait for at least 3 hours as sometimes it may get stuck in customs processing. If it is still not processed after 3 hours, you can contact GeTS to request a status reversal to “DR” which will allow you to resubmit it. However, if it remains stuck for another 3 hours, it is advisable to contact CBSA to check if there is any issue with the submission or if they can see it on their end.