I can confirm it does cost an e-file credit. I followed the steps as listed and had to purchase a credit. Once that is done, request a refund of the duplicate charge here https://accounts.intuit.com/app/oirr. You select Intuit then Proconnect tax. For a duplicate charge they normally approve the request type as credit back onto the account. you would need to include the name of the return the duplicate credit was used on. As long as they can find that proof then they will approve the request.

For business returns:

1. Make a copy of the return after the initial return has been filed and accepted.
2. Go to General ⮕ Electronic Filing ⮕ Superseded.
3. Select the File superseded return box.
4. Transmit the copied return with the superseded checkbox marked.