Here's the fix for anyone wondering.
So the problem resides that you cannot use unrar-free. They have slightly different arguments than just unrar for the unpacking plugin. Now you can go in and change the sh unpack script for each file type to cater to these specific arguments or install the correct package.
You will need SSH access for this. If you do not have SSH access, point your seedbox provider at this post.
You will also need to know your system's architecture.
Type this to get it:
So my server has an architecture of amd64
Click on your architecture on this page:
wget your package depending on your architecture
Code:
wget http://ftp.us.debian.org/debian/pool/non-free/u/unrar-nonfree/unrar_3.8.2-1_amd64.deb
Install the package. Make sure unrar-free is removed before doing this. Replacing unrar_3.8.2-1_amd64.deb with the package you just wget'd.
Code:
dpkg -i unrar_3.8.2-1_amd64.deb
And done. Problem fixed.