Wiring help

Hi, I had a Andorid headunit installed earlier this year, few weeks back it broke and I sent it back for repair..

I've received the headunit back mow and gone to install but nothing is happening on the screen. Looking at the wires from the previous install a few of them have been cut. I'm trying to get my head around what's missing. I'll post a pic, much appreciated if you couldo have a look at the wires and see what his done?

I originally had the HU installed at a local auto electrician shop by me. This was months back, everything worked correctly but the HU had a fault so i sent it back for repair...

I've now gone to put the head unit in and as you can see, the wires have been cut. I think a block might be missing from the quad lock as well, I know with the android head units there is an issue with getting the rear speakers to work, is that why he would of cut wires?

Not sure what i should do next tbh, really don't want to take it back to the cowboys that butchered it the first time.

I've had a look at the wiring, just seems to be the rear speakers now working.

On the exisitng wiring loom, 2 purple wires are connected to a green & grey, i also have a grey & blue wire cut on the loom which i'm unsure of.

do i need to cut the wires from the HU harness to connect directly to the loom?