If you wish to verify the authenticity of any summons you can contact the court that is cited on te face of the summons to determine if a case has been created and you are a named defendant.
Most of these documents are fakes.
The intent is to get you to contact the scammer, who wants you to fork over your cash.
You can also search certain items on the face of the document, and you'll see if its part of a massive scam.
There are many others and a Google, Yahoo, or Bing search will offer you more information.
Last, but extremely important: Don't victimize yourself by conversing or corresponding with scammer/collectors. Its best to avoid all known collection scammers!