changeover from Sallie Mae to Navient

I have been unable to log in to my account since last August 2014 due to the changeover from Sallie Mae to Navient. I have emailed them but I got no reply. I have unable to pay my loans as a result. The Navient website is not working. I tried calling them but there’s only a recording. I could not get a live person to talk to. I live abroad and I have been paying online since 2004 without any problems. This changeover has been a disaster. I won’t pay any fees for their incompetence. I don’t know what to do as I can’t also pay by mail. I hope someone can help me.