How do I delete a connected account? I have duplicate entries in one of the accounts.

Not to worry, contact-kevinmat.

I'm here with all the information you could ever need on deleting a connected account in QuickBooks Online.

When you connect an account to online banking, QuickBooks automatically downloads your recent transactions. Instead of deleting it, I would suggest disconnecting the account. With this, QuickBooks deletes transactions that still need to be categorised in the For Review tab. 

To disconnect an account:

1. Go to the Banking menu or Transactions menu and select the Banking tab.
2. Choose the bank account.
3. Click the pencil ✎ icon, then select Edit account info.
4. Select the Disconnect this account on save checkbox.
5. Select Save and Close.

You can check this article for more information about disconnecting bank accounts in QBO: Disconnect accounts connected to online banking in QuickBooks Online.

Also, you can refer to this link for additional guide on managing your bank accounts: Make an account inactive on your chart of accounts in QuickBooks Online.

Know that I'll be around to help if you have any other questions. I'd be pleased to assist you. Take care!