I have thousands of songs in my usb 2.0 stick which I plugged into the usb c port in my Octavia via an usb c adaptor. It shows under media as usb partition however after opening it it says no media to play or something like that. I formatted it as fat32 and also ntfs but neither way i can get it to work. The stick works well in my oldrr cars with usb a ports.

Glad to hear that I'm not alone ;-) 
See this thread: 

 

I had a similar problem with using an adaptor - If you buy a mini or micro USB C stick that will work fine.

 

https://www.mymemory.co.uk/mymemory-256gb-dual-usb-c-usb-3-1-flash-drive-200mb-s.html

I've tried two diffrent USB-C sticks. None of them works. The infotainmentsystem crashes when I try to play mp3's.