I just logged back into my account after a while with Wizards. As I wanted to look some items up from purchached sources (e.g. the DMG, MM and PHB) I found out that I was being directed to the marketplace again, despite having purchased them and already activated them around Black Friday last year. Upon further rolling for investigation I noticed that things like my made sheets got whiped too, like my account is a brand new one. So characters, purchases et cetera under this email are gone. As I am able to login to Wizards still it only makes the situation more peculiar.

As previewing this specific threat shows that my date of joining is today it only raises more questions. Taken the assumption that my account under this email address was deleted, I wonder why I would not have been informed about this... I do remember my old username being gaudelupae 

Any help, or expanation on the situation would be appreciated, for I am no longer sure what happened

Most likely your old account was created with a different login method, like Google or Apple, and you logged in today with a different, unrelated Wizards account.

Try logging in with your Apple account or your Google account instead. If it's an older account, you might also have used Twitch.

Sorry for the late response, As you mentioned the other accounts I did get an idea that that would possibly work, as I might also be able to sign in with my Twitch.

Unfortunately signing in this way also made a new account.