I have managed to link my bank account twice how do i remove one?

You've come to the right place for assistance, pjands.

Let me assist you with this and provide you with further help.

To start, you'll have to undo the banking transactions that were added or matched and caused the duplicate issue. I'd be glad to show you how:

1. On the Bank transactions tab, go to the For review section.
2. Mark the added or matched transactions and click the Undo button.

Once done, you can disconnect the bank account by going to the Banking tab.

Here's how:

1. On the left navigational panel, look for the Transactions menu.
2. Go to the Banking tab.
3. Choose the tile for the bank account.
4. Click the pencil icon, then choose Edit account info.
5. Choose the Disconnect this account on save checkbox.
6. Hit Save and Close.

After that, you can reconnect the appropriate bank account.

Additionally, I'm adding this article that you can browse for you to be able to categorize transactions uploaded to QuickBooks Online: Categorise online bank transactions in QuickBooks Online.  

You can always count on me if you need a hand managing your bank accounts in QuickBooks Online (QBO). Feel free to let me know in the comments below. Keep safe, and have a lovely day.