[vlad_a]

^^^^
From what you described, the install shop did a poor job, killing a few components in the process.

 

[vlad_a]

An example would be running a 2 ohm sub on an amp setup for 4 ohms.

There is a number of ways one can fry equipment.

Considering how many things are dead or not working in your setup after the attempted install, I would be put shop's competency to question.

All of this, of course, if you had working equipment in the first place.