A bug in the tool, which we use to create search-engine-friendly URLs changed our whole URL-structure overnight, and we only noticed after Google already indexed the page.

Now, we have a massive duplicate content issue, causing a harsh drop in rankings. Webmaster Tools shows over 1,000 duplicate title tags, so I don't think, Google understands what is going on.

Right URL: abc.com/price/sharp-ah-l13-12000-btu.html
Wrong URL: abc.com/item/sharp-l-series-ahl13-12000-btu.html (created by mistake)

After that, we ...

• Changed back all URLs to the "Right URLs"
• Set up a 301-redirect for all "Wrong URLs" a few days later

Now, still a massive amount of pages is in the index twice. As we do not link internally to the "Wrong URLs" anymore, I am not sure, if Google will re-crawl them very soon.

What can we do to solve this issue and tell Google, that all the "Wrong URLs" now redirect to the "Right URLs"?

Best, David