Head Unit Help

[KishanRaguras]

When I purchased my Astra J, it was already fitted with an aftermarket head unit from car vision. This meant that I did not have the 4 line display, which I had purchased separately off Ebay, assuming this would work straight out of the box. I fitted this, along with a Kenwood DMX8019DABS head unit, using the Connects2 cables, etc. The head unit works completely, however nothing is appearing on the 4 line display, assuming the unit works, and the steering controls are not working (for volume, etc), and the change of the heating, etc in the car is not appearing on the head unit. 

I had purchased this all from dynamic sounds, and they have already gone through the troubleshooting of the dipswitches, order of plug-in, etc. They suggest it could be a problem with the control box, which I would need to return, so they can issue a new one. However, I have a slight feeling that this might not fix it either, not sure why though. Any possibility that car vision would have made some changes that would not allow me to easily change the head unit? As in changing and making their own wiring looms...

I have no expertise in this field, if someone could give any advice if they have encountered this before too?

Will be returning the control box on Monday.

Much appreciated for any help given!
Apologies if posted in the wrong forum, and I could not find any threads that were in a similar scenario.