Apple iCloud storage unsubscription (dark patterns)

My mum mailed me to see if I could help her unsubscribe from a recurring payment she keeps getting for additional icloud storage. She no longer owns an Ipad and doesn't know how to disable it.

I thought I would do it for her: https://support.apple.com/en-ie/HT207594

Is this even legal, from what I can see there is no web based way to do this. I am forced to either own an apple device or download icloud for windows.