I can help you with canceling your QuickBooks Accountant Online. You can cancel your account through the Billing & Subscription page.
Once canceled, your account will be available in read-only access for one year from the cancellation date.
To cancel, here's how:
Click the Gear icon on the top menu.
Choose Account and Settings and click Billing & Subscription.
In the QuickBooks section, select Cancel (paid subscription) or Cancel Trial (if you’re using a trial).
Choose Continue to Cancel, then Continue to Cancel again.
Finally, answer the exit survey questions (to help us make QuickBooks better), then scroll down and select Confirm Cancel.
After that, you'll receive a confirmation email for the canceled subscription. You can get more details about this process in this article: Cancel your QuickBooks Online subscription.