How to cancel iCloud storage subscriptions from a non-Apple device?

I'm having difficulty canceling my iCloud storage subscription, which is being billed to me monthly. I no longer user Mac product and am accessing content from my PC or Google phone. Following guidance from the Apple Support site, I downloaded iTunes to manage my subscriptions and cancel the account; however, the account information show there are no subscriptions, yet I'm being billed every month and when attempting to delete the card payment on file, I'm not authorised to delete it because there is an active subscription.

Seeking advice for how to cancel my iCloud subscription without using an Apple device. Feeling quite frustrated as this has been a challenge for several months.

Kind regards,

Frustrated with iCloud