Sallie Mae / They tricked me

I defaulted on a Sallie mae loan yes things happen so I made arrangements to be on a payment plan 460 for 3 months then 250 for 4 months then 2 payments of 1600.00 bucks to settle the loan I worked over time on my new job to get the money and it hurt... I was told I would get a letter saying the loan was settled called after the funds cleared they said it would take a few weeks will I checked my account I still owe 3200 bucks and I am getting the run around.. they are saying that Sallie mae does not do settlements and I need to keep making payments mind you my next payment is not due until 2010 but I can still make payments to Sallie may on a loan that is suppose to be defaulted how is that when I try to talk to them about it they keep hanging up the phone on me or giving me other numbers to call...when I call there collection side I was told that the money I paid was not a settlement but a good faith payment WTF??

so after paying 6300.00 on a 5000.00 loan I still owe 3200.00...also they are saying my next payment is do 2010 ($115) but I also owe collection fees of ($213) also due in 2010 when I asked how is this I got another number to call.