It's been like this for a while now, don't know what's up. Tried the installation on Ubuntu, works perfectly. I used this (https://github.com/servisys/ispconfig_setup)
It downloads and installs packages in the background, this can tale some time depending on the internet speed of your server and system speed.
The install on Ubuntu was not as slow as this though, this isn't even moving giving me any updates. How big are the basic packages?
That can be a few hundred megabytes. Open another shell and check the disk size to ensure that it is not full.
I've reinstalled the server to Ubuntu 14.04 and it worked perfectly, took around 30 seconds to get the basic packages where as the Debian was stuck there for around 6 hours and still didn't move.