Unmetered disk space is no longer offered. My understanding is this is an issue with support in DirectAdmin and also to reduce abuse. You can request size increases here on the forum.
My recommendation is to try to trim it down as the admins don't make big increases all at once. Make sure that files aren't backups or other files that would not be approved. And, the limit on inodes (every file, folder, link, etc. is an inode) is 50,000, regardless of the disk space increase. I'll ask an admin to review your account for compliance and possibly increasing your disk space.