Billing

This is a user to user forum, you are not addressing Apple. As users like you, we have no access to your account to do anything.

The fact that it has been recently paid, should not prevent you from cancelling.

It will not immediately expire however. It will wait until its renewal time before it can expire. But it should let you select the free 5GB option now and then just wait until renewal to expire.

If you wish to request a refund to Apple, fill in the following form: iTunes Store - Contact Us - Apple Support

Select Account and Billing.

You cancel it by downgrading to the free 5GB option. Follow the steps here: Downgrade your iCloud storage - Apple Support

Start here : https://support.apple.com/en-au/HT202039