Lost admin access, all CSS to edit, have no editor at all

Hello there,
i wrote previously and never heard back. i really need some support here as i diasbled all plugins, and that did fix the problem — i basically have limited access to my own back end as to what i can do and it’s super important that i be able to install plugins if i wish and edit the CC to place ad codes.
I tried using a different theme and this did not fix the problem.
would REALLY appreciate some help here!