Solution:
You have not made it clear if you own the site or just write for them.
If you are not the owner, you will need to contact the owner and explain the issue. If they are not able to sort the issue themselves, the simplest solution would be to get the owner to contact the hosting company and see if they can rollback the site to before the issue occured.
If you are the owner, you will need top contact the hosting company directly.
There is no way you can repair the issue without FTP access.