Yesterday strangely some other phone used my account. (A phone model i am not familiar with). I logged all accounts to be sure.
and today all my 7 years lists are gone. I had spent years to create them.
what can I do to bring them back?
I recommend you also change your password because if they got in once and you don't change the password they can log back in. To get back your playlists just click on this link and click the playlists you want back.