Is it possible to undo a flat file upload?

I was recommended to download a full inventory list of ASINs and their listing data, to only edit a value that needed updating for multiple listings and submit it. Although apprehensive I went ahead with it only to come to find much of the data in the flat file was out of date from what the listings currently are, including their images.

Now I have untold amout of listings with any amount of outdated information and old images.

Is there any way to have this undone? Is this something the support team can resolve? Usually when I ask for their help I get canned responses that don’t actually address the issues at hand.

Any help is appreciated.