Loss of power to the sound system. Can it be the ground?

I have a 2008 volkswagon rabbit. The sound system has stopped working completely. I’ve checked the fuses and none of them are blown. It is a stock 2008 vw rabbit 4 door which came with the upgraded sound system option. I did not add any sound system components to it at all.

This sound system issue didnt happen randomly. I woke up one morning to my car battery dead. I went to jump the car and actually i placed the jumper cables in the wrong order. Meaning i made a closed loop between the two batteries (DOHH!). I hooked the negative on my battery to the positive on the other guys car battery. I guess this is what happens after being in a rush.

Anyways i went to start the car (with the batteries hooked up incorrectly). I actually did turn the key maybe 2 times then realized i was gonna melt the battery if i kept trying. Some observations when trying to start the car with the cables hooked up incorrectly:

1. the car did not respond at all when turning the key. It seemed to have zero power which makes sense i closed the circuit between the two batteries.
2. When i went to grab the jumper cables to disconnect them they were very hot.

After reconnecting the cables the correct way my car started with no problems. The only issue was that i had no sound system. Not even a flicker and it still has never turned on since. There does not seem to be any problems with anything else in my car. all lights turn on fine.

This is what brought me to test the fuses but none of them were blown. I’m curious is it still a possibility that there is now a melted ground wire somewhere even without a blown fuse? How about did i damage the sound system? Melted some other wire? Any tips?

Car: 2008 VW Rabbit 4-Door.

Thanks,

Dan