Hi Chris,
Don’t know if this will apply to you but I had a similar problem when I tried to upgrade (round about Dec 19th). Paid, got a confirmation email, but there was no Activation Code in the section for retrieving the download, and the links in the email were not taking me to live pages on the Avid website. I called Avid support and they walked me through the My Products and Subscriptions page, pointing me to a different tab than I was used to looking at. If you take a look at that page, and check the “Media Composer – Standard Support” “tab”, which probably will sit below the listing for the most current purchase of Media Composer that you own (in my case, the Standard Support table also says “upgrade from Symphony”), there you should see your perpetual product listed, plus the Standard Yearly Support that you’ve just paid for. If they haven’t confirmed your old license, you may see “On Hold” rather than “Active” next to the words Standard Support… and it might be another day or two before they get to you. Below that should be good links and an activation code that’ll get you 8.3. My experience with Avid support was very good, and I was even a temporary activation code… but I had started a claim at the beginning of the week. Given that it’s the weekend, I don’t know if Avid support will be able to solve the problem for you by Monday. Couldn’t hurt to call them, though.
Happy New Year!