Navient attempted to cash the check

In anticipation of business travel, I prepaid all of my November 2012 bills with post-dated checks, including Navient . Unlike all of the other companies, Navient attempted to cash the check prior to the proper date, despite my inclusion of the November billing slip in addition to the check to make clear how payments should have been applied. As a result of Sallie Mae failing to perform any due diligence, the check was rejected by my bank because of this dating issue. Rather than submitting the check on the proper date (again, uniquely of all the bills I sent in this manner, some 15 in total), Sallie Mae marked my account as delinquent and reported this false delinquency to the credit bureaus. In the 8 years since my repayment period began, Sallie Mae has never once gone a continuous year without billing issues, ranging from this, to failure to provide payment books for months after new books should be issued, improperly crediting payments in excess of the minimum amount, changing me over to electronic notification without my consent (twice), etc. While I have always acted in good faith to repay my loans and made every payment on time and in full, Sallie Mae has repeatedly failed to properly service my account. At this point, I can no longer assume that they are acting in good faith, as their response to each and every error has been to try to force me into an automated payment plan with no acknowledgement of error or wrongdoing on their own part. Frankly, I do not trust them, given their extensive track record of errors, not to misuse my banking information. When I graduated I had 3 other student loans, two of which are now paid in full and the third of which will be paid in full this month, and I have never had these sorts of issues with any of them. This is clearly a Sallie Mae issue, one they have refused to correct.