you can’t get them back unless they were rated or tagged.
To add on, here's more information
I'm sure one of the links includes the email for the webmaster, but you'll likely get the same response/ others have said they emailed the webmaster but haven't gotten a response yet.
They're very busy with fixing the site + have gotten a lot of emails these past few days so I assume you'd likely not get a response any time soon
About Lists
https://www.mangago.me/home/mangatopic/21155166/
Latest Update + Don't mess with lists yet
https://www.mangago.me/home/mangatopic/21212683/
https://www.mangago.me/home/mangatopic/21213931/
FAQs at time of site crash
https://www.mangago.me/home/mangatopic/21080691/
My list havent updated for two weeks and I REALLY need my lists and im gen so attached to it Is there a way I can email anyone so I can get my list back