Yes. Corporations (and/or their agents) can be sued for slanderous or libelous behavior. Slander and libel laws vary from state to state, so check with a licensed attorney where you live.
You can sue anyone for libel or slander with enough evidence. However, Congressmen cannot be sued for anything they say on the floor of either House of congress as part of a vote or hearing.
My sister has written a letter to my other sister with a lot of lies about me. She has been telling these lies for over twenty years, these lies have caused me untold anguish, has alienated my two...
You definitely can, but wouldn't it be easier to just ask them to take down the information you found libelous? They are very accommodating and usually remove the information within 2 working days....