Hi e edwards,
Welcome to Microsoft Q&A Forum.
It's a pity to hear that you are stop using Microsoft service. I understand that you have met some error situation, and you can share on the community here to seek the answer for your issue.
Regarding the cancellation request, here is the Microsoft's link that can help you request the cancellation on your end: Cancel a Microsoft 365 subscription
Please remember to request the refund on your end, because not all the subscription is eligible for the refund process: How to get a refund on a Microsoft subscription
As a Moderator, I and fellow users are unable to resolve the case with your sensitive information on this online forum. Hence, if you need further help, please let me know so I can share the instruction to help you reach out to Microsoft Support directly.
Once again, thanks for sharing and apologize if the service is not met your expectation.
Thanks, and sincerely,