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I am wondering if there is a way to revert back to the old setting, keywords, ads, and costs from before they took over the campaign.
Gosh, I assume you didn't have an Excel export of the campaigns, ad groups, and keywords - did you? Without this data... and unless they deleted the campaigns as-is and created new ones, where you could simply "undelete" the old ones... I think you may be, unfortunately, out of luck.
As far as keywords/adgroup data goes... Google keeps an extensive change history. Not sure exactly how far it goes back but I believe it's at least a year. You can go through that and see exactly what was changed from the time you let go of the campaign. You may not be able to retrieve every piece of info but you should be able to get most of it. I believe it's under tools, My Change History in the adwords interface.
As far as keywords/adgroup data goes... Google keeps an extensive change history. Not sure exactly how far it goes back but I believe it's at least a year.
From Google's UI: "Browse changes you've made to your account since January 1, 2006." The format of how these changes are logged may be a challenge, but that should be a start!