Sallie Mae Incompetence with handling loans and poor communication to consumers, Internet

I have had a student loan with Citibank since 2000 and have always paid on time. I have enrolled in classes several times since I started paying my student loan, and when I enroll, Citibank has always deferred my loan automatically until I finish. I enrolled in classes in August 2011 and when I did not receive my loan statement I was not surprised because it was Citibanks standard policy. However, when I did not receive anything from them at the beginning of 2012 I was concerned. I did not receive a tax statement nor did I receive a bill.

I went online to research and found out that citibank no longer had my student loan. In fact, my loan was bought by Sallie Mae, I called them and they stated that my account was 120 days past due. I never received anything from Sallie Mae indicating that they had purchased my loan nor did I ever receive a bill. When I called them, they didn't even care about my complaints and only said they did send me an email. I get a lot of junk emails and do not look at ones that appear to be junk mail. Since, in the past I had no relations with Sallie Mae, I was not concerned about an email from them. Now my credit has a major flaw and my rating has dropped because of Sallie Mae and they could care less.