If you are reading this article, then you must have made a blunder!
No worries, if you are within 3 days of that user being deleted, then we have your back! Go to 'Insight' -> 'Deleted Users Report'. All the recently deleted users will be in this report. Here you have the option to 'Restore' the user(s) that were accidentally deleted. This will restore the users accounts back to exactly what it was like before they were accidentally delete.
If the user is not here, then that means it has been more than 3 days, and sadly, not even Superman can bring them back. You will need to add them as a new user back in the system. To confirm the termination, go to 'Insight' -> 'Orders' and filter by 'Terminations' to confirm that a user has been permanently delete. In this report, you can also see how much was remaining in the users balances if you need to add that back in.