I had my oath done on July 5th and file closed couple of days later but the certificate never arrived. I emailed them to enquire about it, they replied by saying it has been mailed out on July 11. Even though its clear that my certificate is not gonna arrive , since it has already been a month after they claim they sent it. They simply want me to wait until 6 week mark is completed so they can start processing to issue a new certificate. After looking at other threads apparently some certificates goes missing with no trace. even then IRCC don't think adding tracking numbers is useful. After my oath is done I was happy that I never have to deal with IRCC again. It didn't last long.