I have a similar problem with a lost deck. I’m pretty sure it was synced up with AnkiWeb because I would sign on to the website from my phone to use it. Unfortunately, my iPhone and Mac are both dead so I don’t really know what to do now. Also for some reason, AnkiWeb doesn’t even show the shared decks I have but I can see them on the application…
I’m afraid your account appears to have expired due to inactivity. If you’ve lost your data on all your devices, it unfortunately will not be possible to recover it.