My name is Rae, and I work for Shopify.
I absolutely understand your frustration with still being charged for your Pinterest account after it's been deactivated, and I'm happy to help share some next steps to get this resolved.
If so, this app is fully supported by Pinterest, so it's best to speak with their Support team about this directly. Please reach out to them via email using the email address email@example.com and supply their team with the following information:
Once you contact Pinterest with these details, they can help investigate this situation further, and confirm how to get this resolved.
Please keep me posted on how this goes!