Advice on speakers, amplifier and system.

Dear forum.

This is my very first post. I am absolutely delighted that I have finally bought my (first) Eos. Ever since I was a kid, I loved this car. I bought the 200hp 2008. TSI highline (2009 edition) dsg automatic.

There's only one problem, all the large bass speakers are not functioning at all. There's no crackling sounds, it's just silent. When reading out the car, the error message is 'circuit broken' for all 4 the bass loudspeakers. I thought this would be an amp issue, but the 6 other smaller speakers do have sound (only high tones I guess).

My mechanic says the speakers are broken, because when he connected a speaker that he had lying around, the sound did work. He's a very cool guy, so he's allowing me to buy my own parts for him to install.

Therefore, I need help with the following:

1. I would like to refit the 4 broken bass speakers with good quality ones. Maybe the Dynaudio package? Only, I have no idea what these sizes are. Does anyone have a link for me that entails the proper speakers (front and back) to replace the current broken ones? I have been looking around in this forum and the rest of the web in order to make sense of it all, but I can't filter through all the information. (An EAN for the parts would be even better).
2. Does anyone know which exact audio system can be placed in the EOS, that has apple Carplay and bluetooth etc? An audio specialist who listened at the sound told me that the only problem seems to be that the current system isn't stock and that the speakers are fine. In my honest opinion, I think he's just trying to sell me a 1200 Euro system that I can buy for 300/500 myself. I also trust my mechanic. If it was the system, it wouldn't be possible for the mechanic to just plug in another speaker for it to work (right?). Anyway, I've added some pictures to show you my current specs.

I hope you guys will be able to help me. I am not that technical when it comes to audio, therefore I am very lucky that I found this forum

Thanks a lot in advance.