Complaint sub-issue: Trouble with how payments are handled

I am currently unemployed and I have been waiting since XX/XX/XXXX to have my request for Income-Driven repayment approved which has not been granted to date due to a billing error and processing delays from Fed Loan Servicing. Here is a log of my phone calls, emails and noted documents which show my due diligence to have this remedied and the negligent manner my request has been processed. 
XX/XX/XXXX : Called to get advice on repayment difficulty because I was unemployed and could not make payments. I was advised by XXXX on XX/XX/XXXX that since I was unemployed, I should apply for Income Driven Repayment plan-that the easiest way to apply for the Income Driven repayment plan was to fill out an application online, which was emailed to me with the link to the application. 
XX/XX/XXXX : I filled out the application online with the assistance from another advisor to make certain that everything was properly submitted and all necessary requirements were fulfilled on my end. Application was approved and expiring XX/XX/XXXX. I called in XX/XX/XXXX to get a status on my application, and was informed that the application would not be processed until I paid a {$5.00} for the XXXX to go into effect. ( I was not informed in my initial conversation with XXXX despite the fact that I asked if there were any additional requirements on my end that were necessary to process and complete my enrollment in the plan ) I requested to make payment by phone, and was informed that I could only pay it when I received the statement-which did not arrive until 1 month later. XXXX XX/XX/XXXX, I received the bill/statement for the XXXX in the amount of {$4.00} to process the application. I paid the requested amount of {$4.00}, which was cashed and posted on XX/XX/XXXX. I paid the requested amount of this bill because I was instructed not to pay anything until this bill was received. 
XX/XX/XXXX, I called to get a status on the application. A loan XXXX informed me that I paid the wrong amount of {$4.00} and not {$5.00}. Subsequently, I requested to speak to a supervisor. I spoke to supervisor, XXXX, who informed me that since I did not submit {$5.00} my application was rejected despite of the fact that the bill amount was their error. He advised me to pay the additional {$.00} online, which I did immediately upon XXXX connecting me to automatic payment. He also advised me that he would request to have the situation corrected and that I should call back in XXXX weeks. He stated that the {$4.00} bill was their error and it would be corrected. He also stated that upon correction the accrued interest would be retroactively forgiven since the error was not on my end. 
XX/XX/XXXX : I spoke with Takisha ( another supervisor ), on XX/XX/XXXX, who also admitted that this was their error and stated that she would get this corrected and she would get back to me in 2 days. 
XX/XX/XXXX : I called back to get a status from XXXX. I was informed that I would now need to apply for a new application. I asked to speak to another " higher up supervisor ''. I spoke with XXXX XXXX, and he also admitted that this was 100 % their error on their end, that the {$4.00} bill from Fed XXXX XXXX has been an ongoing issue and I must have been XXXX of the many and referred me to and file a complaint with the Office of Consumer Advocacy. He stated I did everything I could on my end to get this properly processed and he would fight for me to get this resolved. In addition he referred me to contact supervisor, XXXX XXXX, whom he spoke to regarding this matter. He was told that I would need to file a new application for XXXX XXXX XXXX XXXX since now the application is 3 days past the 90 day approval. The error made on Fed XXXX XXXX automated billing has resulted in astronomical interest at the cost to me.