Thank you for reaching out and posting this question!
I understand you forgot to cancel your subscription and you'd like to get a refund for this charge. While we're unable to provide account-specific support via the Shopify Community, we'd be happy to take a closer look at your account and assist you with a refund through live chat, email, or callback. That being said, before you get in touch with our live support, I'd also recommend closing your store now so that a refund can be issued if your invoice is eligible. Once that's done, simply visit the Shopify Help Center and log into your account to create a support request.
I'd love to hear more about your experience with Shopify, or if you have any feedback to share with us, don't hesitate to let me know!
Elias | Social Care @ Shopify - Was my reply helpful? Click Like to let me know! - Was your question answered? Mark it as an Accepted Solution - To learn more visit the Shopify Help Center or the Shopify Blog