Sorry I took a while to reply, but I did try all of your suggestions. When I tried logging in from the website, which I eventually tried on a different browser and a different computer, I got the "Account not activated" error. When I tried to register another account under my email, it told me that I already had an account under this address, and wouldn't let me do anything further. And for good measure, I went and scoured my emails one last time for anything related to Mount & Blade or TaleWorlds, and the only activation emails I could find were, as last time, ones I already used. At this point I'm pretty sure it's an issue with the website and not a mistake I've made, and I am once again at a complete loss.