I'm having the same issue with this number, calls a couple of times a day and hangs up. I'm just not picking up anymore. Obviously someone needs a hobby.
I'm surprised to hear that no one was responding to anybody here. There was a girl on the other end, who, as I said before, was from Sallie Mae. Sallie Mae has a list of phone numbers that they use to try and trick you into answering. Another popular one they use (which I have seen a page of posts just like this one about) is a Delaware number 302-394-6932. Google that, and you will find alot of posts as well. Hope this helps.