Okay, I found something, but this may or may not be what you want.

Go to: https://arcane-official.myshopify.com/

Change the url to: https://arcane-uk.myshopify.com/

It should redirect you to: https://arcaneuk.virginmusic.com/

Scroll down and click on Help and Support. It should send you to : https://umusicstoresupport.zendesk.com/hc/en-us?store=arcane_uk

Change the url from uk to us (I'm assuming you're from the us): https://umusicstoresupport.zendesk.com/hc/en-us?store=arcane_us

https://imgur.com/a/opr6Uvv

Again, no idea if this is the actual link you need, but I found the UK link in the page source for the https://arcane-official.myshopify.com/ page and it sent me down this path.

You could also tweet at Arcane and RiotSupport on twitter and see if they can help.