Numbers disappeared from iPad

I have had the Numbers clicked green in my iCoud in Settings for years, never been switched off, either are they now. Suddenly some days ago all my Number files disappeared from my iPad, I think after an IOS update but I am nit sure (I am positive I did not erase these files). I have all my students results of all my classes there. Numbers is still clicked on on i iCloud. But when I goto iCloud.com, as suggested by Apple support, I do not manage to find “restore files”. Please help.