Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hello Emma, good day and thanks for your question. I understand that the payment method on your account is already removed but you are still prompted that it will be used as a payment.
If this is confirmed that it is removed, this looks to be system related and you can reach out to the support team at https://support.microsoft.com/en-us/contactus/ and then click on Microsoft 365 and then click Get Home Support and then type in Billing question and click the blue button that says Sign in to contact Support and login and proceed from there.