You’ve already done all that you can do. It is now up to support to decide if they will give you a credit for the time you paid for the editors.
Note that Airtable usually pro-rates charges for the amount of time people were billable, so even if support does not find in your favor, you should be charged for only the actual time they were editors.
Also, if you do receive a credit, don’t be pig it shows up as Airtable credits and not an actual refund on your credit card.