110 ILCS 992/5-10

(a) A servicer shall credit borrower and cosigner payments promptly and accurately. (b) A servicer shall provide borrowers and cosigners with prompt notice if the servicer changes the address to which the borrower or cosigner needs to send payments. (c) A servicer shall not charge a penalty to a borrower or cosigner if a student loan payment is received at an address used for payments for a period of 90 days after the change in address. (d) A servicer shall not misrepresent the delinquent amount of the loan on any call with a borrower or cosigner. (e) A servicer shall allow a borrower or cosigner to specify instructions as to how an overpayment should be applied to the balance of the loan as consistent with the promissory note.