Bad service from Altech netstar caused damage to Bakkie

Dissapointed in very bad service from netstar.I struggled for weeks to get hold of someone to assist me with this at netstar.Unit was installed incorrectly and caused damage to my Nissan Navara bakkie.Its costing me a lot of money and for 2 moths now I don't have transport and have to rely on other people,i am currently paying an instalment on my bakkie which I cant even drive.The technition struggled for 2 hours just to change the unit that was giving problems and after that we coulnd drive the bakkie as all the dashboards lights came on and stayed on and the bakkie didn't want to move.Netstar just refuses to accept reponsibilty even after I received a report as proof that their unit caused damage on the fuse box and everything got burnt.This is ridiculous that they cant take responsibility,i also tried to get the name and surname of the technition that who was working on the vehicle but without success.I am trying to get all evidence from calls and mails that wa sent to them and all complaints and alarms that went off at their offices but also with out success.