Mitsubishi Pajero IV

[Vitor]

I just bought a new headunit 10.1 for my Mitsubishi Pajero IV, from 2007, and despite saying that it is a plug and play unit, the truth is that after everything is connected nothing appears on the screen... it does not turn on, there is no sound ... anything;
I'm getting desperate; Can anyone help me ?
I already asked Joying for help but so far no one has responded...

Hugs from Portugal.