Thanks for reaching out.
Sorry to hear that you have accidentally selected a subscription plan on the wrong Shopify store. We will need to take a closer look into this. Since we cannot authenticate you through our community forums, we will need to navigate to our Contact Us page and login to your store that you would like to close.
This will securely verify you as the store owner and allow you to speak with a Shopify Support Advisor that will be able to assist you further with this request.
Let me know if you have any questions or concerns.