This is probably because you linked your purchase to a different account than the one you are trying to access it with. Are you sure you haven’t made multiple accounts?
As far as I'm aware, I had never made an account before I attached my github to create my current account.
And I've tried the link in my email logged in, not logged in, and in incognito mode.
Edit: I also didn't create the account until after my link had already stopped working.
Edit 2: I created a bookmark of the original link, and had been using that successfully for the first three days, and have also re-clicked the original link in my email numerous times, so not a typo or bad copy/paste issue.
Edit 3: Just realized what happened and confirmed it. My 13-year-old daughter saw I had gotten the bundle, took my link, and attached it to her account. Frustrated, but at this point if she's using it I'm just going to buy myself another copy.