<prompt> Human: Small town girl. I went to a school way out of my league and my budget, but I graduated and landed a good job. I was fortunate enough and sacrificed enough to be able to pay down 17K on my student loans last year. I greatly overpaid several months, but I dont know what Im doing. I now have 39K remaining through GreatLakes that is in paid ahead status until 2020. I thought I was making the extra payments on principal this whole time. Everytime I call and ask them to reapply the payments, they assure me thats not how its done. Heres the question: did I sign a loan I didnt understand, or are they taking advantage of me now on the phone? Can It be that Great Lakes does not allow borrowers to make extra payments toward principle? Any advice or experience? Please shareEDIT: Thanks everyone, this has been very useful. What I didnt understand was that you have to pay interest daily instead of at each payment period.  <response>: I thought I was making the extra payments on principal this whole time.Is that not what your statements reflect? did I sign a loan I didnt understand, or are they taking advantage of me now on the phone?Could you post why you think your payments are being improperly allocated in the first place? From what you write its not obvious how you know theres a problem. 