They aren't deleted you'll get them back.
don't worry, ppl whose acc were made in 2014 and 2015, as in earlier years, slowly got their reads back.
Currently 2017 ppl are getting it back.
https://www.mangago.me/home/people/65330/home/
https://www.mangago.me/home/people/7934/home/
https://www.mangago.me/home/people/12004/home/
so yeahh it'll take quite some time but you'll get them back.
also once they're back, in case you're looking for ways to save them perhaps in an excel file, I've made a tutorial on how to do it easily and quickly rather than having to enter everything manually one by one, so if you'd like, you can check it out.
https://docs.google.com/document/d/14Drj0CviUhrAmZlU-DC-AtxGFQoH1_PYQ81b2Vzu82w/edit?tab=t.0
https://www.mangago.me/home/mangatopic/21071894/
& dont worry my reading manga lists is slowly recovering looks like manga is starting with the old accounts first
Read the FAQS and explanation here
https://www.mangago.me/home/mangatopic/21080691/
As for the concern about site exposure:
https://www.mangago.me/home/mangatopic/21014248/

Not sure if my reading lists going back to zero is encouraging me to quit or to start anew lmao
I had around 800 in my already read and around 200 in want to read, thankfully it was only around 60-70 in my still-reading list since I generally prefer complete works, but still I lost too much