To cancel your QuickBooks Online (QBO) account, you can follow the steps below:
Sign in to QuickBooks Online as an admin user.
Go to Gear icon and select Account and Settings.
Select the Billing & Subscription tab.
In the QuickBooks section, select Cancel.
Follow the steps on the screen to cancel your subscription.
Once you're done, we'll send the account administrator an email that confirms we cancelled your subscription.
If the cancellation failed, I recommend contacting our QuickBooks Online Support Team have additional tools to pull up your account in a secure environment and cancel your account.