Ted here from Shopify, thanks for reaching out to us!
When you have a moment, please log into your account and downgrade the plan to the Basic $29 subscription in the Settings > Plans and permissions > Compare plans as shown here for example. You won't be charged for anything but you will need to downgrade the plan before I can review the account for a refund.
I can also take a closer look into this with you. I wouldn't be able to discuss your billing on a public thread but I have emailed you to authenticate the account. Please keep an eye out for my email.