I think it was deleted because it was not directly Discourse related. I discussed with your colleague Ravi via direct message about how to fix this though I didn’t have any follow up.
It can probably be fixed with a short rails script that will compare names and usernames and split name if needed.
Were these users imported? If they were how did you import them?
Since this topic may also be meant to be deleted, I’ll send you a direct message too.