Q: Refund on 1 TB storage space

See this article:

Annual iCloud storage plans - Apple Support

After you select a new monthly iCloud storage plan, your existing annual plan will be canceled, and you'll be charged the prorated cost (the cost of the higher-tier plan minus the prorated cost of the previous plan). Your plan upgrades immediately, and the new monthly payment date will update to reflect the date of your new plan.

If you want to request a refund, then I suggest usint the Contact Apple Support link at the bottom of the article.