MongoDB will not uninstall

So, it would appear that following the official MongoDB installation instructions when installing on Debian - you're heading for a world of pain. Firstly, it didn't install correctly so now - i'm trying to remove all installed MongoDB packages so that I can start from scratch.

Frustratingly, because it didn't install cleanly (presumably), it won't uninstall.

Originally, I installed using the instructions here: http://ift.tt/1mvzOen

Currently, i've managed to remove every package apart from mongodb-org-server which, just won't go.

An attempted removal results in the following:

user@host:/$ sudo apt-get remove mongodb-org-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
mongodb-org-server
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 23.9 MB disk space will be freed.
Do you want to continue [Y/n]? y
(Reading database ... 31030 files and directories currently installed.)
Removing mongodb-org-server ...
invoke-rc.d: unknown initscript, /etc/init.d/mongod not found.
dpkg: error processing mongodb-org-server (--remove):
 subprocess installed pre-removal script returned error exit status 100
invoke-rc.d: unknown initscript, /etc/init.d/mongod not found.
dpkg: error while cleaning up:
 subprocess installed post-installation script returned error exit status 100
Errors were encountered while processing:
 mongodb-org-server
E: Sub-process /usr/bin/dpkg returned an error code (1)

This is causing me untold problems, any ideas how I can properly and cleanly get rid of MongoDB now?

Jordan