Hey @ij1,
Okay so I was reading this over and over trying to think of ways to recover your files / keep them safe. Question 1 do you have any backups saved? [This can be checked in the "Backups" section of your minehut dashboard] Question 2 have you tried re-adding Advanced Bans and then clicking "repair server files"?
If you have tried everything the one thing I can recommend is going to "Danger Zone" then clicking "Reset Server" this will remove EVERYTHING on the server though so please only do this as a last resort if you have to because I can not offer any more support!