I do not know what those files are. I was able to find "ssv3_backup_payload-hCWbWs7TPo.php" and backup then delete it. I could not find the other file even with search.
Still gives me the 500 Internal Server Error. Also, now my website is down, yesterday is was still working, but this morning it give me "Forbidden, You do not have permission to access / on this server.