If you accidentally created a duplicate QuickBooks Online account, we can manually delete it by changing the last word of the account's URL to purgecompany. Once done, the next screen will provide a summary of the items to be deleted. You'll just have to enter the word “YES” to confirm the deletion and select OK. Then, click Wipe Data once your selections are complete.
However, if your account is more than 60 days already, we're unable to purge it anymore. In this case, we'll have to cancel the subscription. Then after a year of being inactive, it will automatically delete all your company data. Here's how:
But, if you're trying to delete a duplicate account in your chart of accounts, we're unable to delete them. Though, we can make them inactive so that they won't appear in your Chart of Accounts. Here's the link: Make an account inactive.