<prompt> Human: What gives?edit: FWIW, this is not urgent, as I paid the full balance today  <response>: If youre on a graduated or income-based repayment plan, chances are youve accrued more interest than youve paid off so far. Either that or if you went through a period of not making payments even if they werent due and the loan accrued interest during that time.Also if you have multiple loans, interest for all your loans must be paid off first before principal is paid for any loan. Some people that run into problems like this will find that all their low-rate loans have zero interest accrued while one still has a pretty substantial sum. Sallie Mae will strategically apply automatic payments this way because it results in more money for them.So check every loan and make sure all the interest balances for each one are zero. You wont be able to chip away at principal until that happens. 