I disconnected my bank account link and want to reinstate the link so everything is as it was. How do I do that without duplicating data?

Hello there, @mb88. Thanks for reaching out to the Community. 

You'll need to exclude the bank transactions from the For Review tab. This way, the transactions will move from the For Review tab to the Excluded tab. From there, you can delete the transactions by selecting Batch actions, and clicking Delete.

Here's how to exclude the transactions:

1. Go to Bookkeeping, select Transactions, then select Banking. 
2. Select the For Review tab.
3. Check the checkbox of the transactions to exclude.
4. Click the Batch actions drop-down and choose to Exclude Selected.

After that, you can now delete them from the Excluded tab. 

For additional information about excluding and deleting bank transactions in QBO, feel free to scan through this link: Learn how to exclude a downloaded bank transaction.

However, if the problem continues, I'd suggest reaching out to our Customer Care Team. They have the tools to help investigate this behavior's root cause.

I'm just a few clicks away if there's anything else you need. I'll ensure you're all set. Wishing you all the best in everything that you do.