Complaint sub-issue: Account status incorrect

AES Student Loan Servicer reported me as " major derogatory '' for a {$14.00} payment that they failed to collect from me when I called several times to their office to begin ANOTHER repayment plan. I have called wrote letters since XXXX to rectify this situation as my credit score dropped from an XXXX to a XXXX. I have since lost a bid on a new home, and had to find a co-signer to purchase my new vehicle. Note : I WAS ON AN AUTO REPAYMENT PLAN WHEN THEY REPORTED MY CREDIT!! After several conversations, supervisors, and writing appeals to AES, I am still left struggling to rebuild my credit ( which had been in good standing for quite some time! ). Below is the last letter I wrote to the appeals office, per their supervisor-who helped draft the verbiage for me. And I was still denied. 

" Per my conversation today with XXXX, ID # XXXX, I am writing regarding the denied credit dispute that I sent in last week. He stated that I should write an appeal to clarify my reasoning for the dispute. 
On XX/XX/2022, I called into your office regarding a bill that I received in XXXX for XXXX for {$14.00}. I explained that I didnt understand the purpose of the bill as I was set-up on an auto payment status. The person on the phone stated that I needed to be re-certified for the Income Driven Payment Plan and then assisted me in doing so. A payment agreement was set and it was my understanding that this would also take care of the {$14.00} balance on the account. At no time during that recorded conversation was I instructed or asked to pay the {$14.00}, or I would have immediately. 
The auto payments went on as scheduled and then on XX/XX/2022 I received a notification of a derogatory credit report for non-payment of {$1700.00}. I immediately called back to AES to question this report. The lady that I spoke with was very helpful and stated that Loan Sequence # 1 was showing a {$0.00} payment due and therefore the auto payments were not being contributed to that particular loan. However, it was not disclosed at that time that the {$14.00} was not cleared and therefore the reason for the negative credit report. She stated that she recognized the error and would send over a request to have the derogatory reporting removed. I was at ease knowing this was being handled. 
XX/XX/2022 I received another negative credit reporting for {$1700.00}. Due to these two reportings, my credit score went from an XXXX to a XXXX! I called back to AES as I thought this matter was rectified. The person that I spoke to this time stated that they, too, would process a dispute. I wasnt made aware of a form that needed to be completed, but then received a dispute form in the mail on XX/XX/XXXX. I then called back to AES to ask why I was receiving a form nearly a month later when twice now I was told the matter would be resolved. This person said I had to complete it in order to request the removal of the derogatory reporting. I completed and uploaded, and mailed the form as requested. I called back today, as instructed, to check on the status and was told my request was denied. 
While XXXX explained that the {$14.00} was a past due amount, he understood that there was clearly miscommunication and could see by my account history that I have been making every effort to remain in good standing with my payments. 
It is my hopes that whoever is reviewing this correspondence can see that I am in no way attempting to avoid payments and doing everything in my power to cooperate. For what its worth, my family and I just lost a bid on our first new home due to this credit reporting and we are absolutely devastated. Additionally, I have a new vehicle waiting to arrive from the plant and I am truly hoping this can be rectified prior to having to sign papers on a new lease. 
I have worked extremely hard to maintain a good credit score and would graciously appreciate your understanding to submit a correction on my behalf. After hearing XXXX explanation, I do understand that the {$14.00} was a delinquent amount, but I urge you to pull the recorded phone conversations to see why I was left under the impression that my AES servicer was leading me in good faith and did not speak of a need to pay the {$14.00}. I believe both myself and the representative understood that the approval of the repayment plan would also include that amount. 
Thank you for looking more deeply into this situation. I will await your response. '' This, too, was denied.