Delete everything from your FTP client, if it does not delete it from console:
rm-dfr / Remove a directory folder is empty but not
rmdir / folder deletes empty directories
To access the console you can use server using Putty or similar program, you can find the connection settings on the same page of the manufacturer.
Now you see panel 1-click installations, press installed applications, select the domain, and uninstalls WP, after that, I can reinstall, I hope that even later, it helps you