Why do your people mess with the database via script during live servers?
What measures are taken that this will not happen again?
What about chars that were unactive, might they have lost items?
What were the conditions under which items got deleted?
Are you seriously expecting a manual approach to work (many players don't do books on the items they have...and not all sort their inventory (like me) so they see things at first glance). Still i would have to log through and check all chars...)?
If you wanted to fix an exploit (rather a bug YOU created), why are people affected, who had no duplicated items?
Don't you have daily backups for a rollback?
How will this issue be treated, if some players find out next year or so, they are missing an item?
Sorry, but the manual approach to fix a script created issue is just wrong. Professionally wrong. Don't your people understand their own scripts? At least don't harass your customers more by requiring them to petition. Look at your script...backtrack what it did...and FIX it yourselves during a downtime or with a counterscript! How could you even let people loose live on the database, who can't even undo the mess they created or at least report and document it properly and fast once the first customer complained??
Sorry again for the harsh words, but in any other industry this would be completely unacceptable and the handling so far is just horrible (though i appreciate the explanation, but one could deduce as much already by what happened). At least let someone answer the questions above or give more details about the script. Mistakes can happen...but it is the handling of them that defines good work.