If a rejected bank transfer is in undeposited funds..do you need to create a new deposit ?

Hello, khegge. 

There's a different way of handling a rejected bank transfer. I'll show you the steps below on how to do this. 

Since we confirmed that the bank transfer is sitting in your Undeposited Funds account, you'll want to credit a service item to track it. 

Here's how: 

1. Click the gear icon and select Products and Services.
2. Click New, then select Service.
3. Type "Rejected bank transfer" or similar for the name and set a description for it.
4. Select Undeposited funds for the Income account.
5. Click Save and close.

Next, create a new invoice to record the failed bank transfer: 

1. Open the + New menu. 
2. Select Invoice.
3. Select the customer with the failed bank transfer. 
4. Add the rejected bank transfer item you created.
5. Enter the total amount of the rejected payment.
6. Click Save and close.

Finally, remove the original payment from the invoice to denote that the payment was not processed properly: 

1. Open the invoice that has the rejected bank transfer payment.
2. Click the Payment link to open the rejected payment.
3. Uncheck the original invoice, then select the new one you created.
4. Click Save and close.

You can check this article for more details about the steps above: Handle a rejected or failed bank transfer payment. 

If you also need to take care of your bank transactions (if you use the Online Banking feature), you can read this guide: Categorize and match online bank transactions in QuickBooks Online.

This can help you match or add your bank transactions properly. 

Do you have any other questions when managing your payment transactions? Do let me know and I'll help you out. I'm also down to answer any other concerns you might have for QuickBooks.