Complaint sub-issue: Received bad information about your loan

I have been dealing with XXXX XXXX for the last year, trying to get a reduced IDR payment based on my XXXX AGI - per industry standard. The first time I applied for a new IDR rate with my tax return, they took months to respond then said I did it incorrectly. Next I resubmitted my application and they said that since the tax return was more than 90 days old I had to submit a paystub, which was higher than the rate I would have gotten had they used my AGI. Later that year, in XX/XX/XXXX I started a new business so I called to find out what I needed to do to claim my self employment status and how I could prove my income. I spoke to a customer service rep and they told me to write and hand sign a letter attesting to my status and list my income for the past three months, since the pay wasn't regular. I did that and waited two weeks when I got a letter my application was incomplete. I called back and they said I have done everything correctly. The customer rep promised to resubmit and expedite because I had a payment due soon. By the time my payment for XXXX was due I still hadn't received any positive news that my application had been processed. In constrast my similar loans through XXXX XXXX had been approved weeks ago at a much reduced rate reflecting my new income. After I went back into forbearance while waiting to process the application, I got another email saying my application had not been accepted - for the same reasons as before. I called again and again the customer service rep said it should be fine. I spoke to a supervisor who also confirmed that I had done everything correctly. They assure me that my application would be approved before my forbearance days ran out in XXXX, when my new payment was due. The weekend of XXXX XXXX, as soon as their offices closed for the long holiday weekend, I received an email saying my application was not approved. I had to wait 3 days to call them - at which point it was be impossible to reduce the amount that was due for XXXX. I spoke to two reps that following Tuesday and finally a supervisor explained that I had been misinformed about what I needed to submit for my IDR to be approved given my new self-employed status. I sent him the required bank statements that he said would be sufficient and magically within two days he was able to approve my application. I told him that because this long wait time was XXXX ' fault, that their employees were misinforming me for months, they should 'refund ' my forbearance days that they wasted as well as make my account current so I didn't have to pay the high/incorrect bill for XXXX. He said he would file a request with a different department that should handle it within the month - or at least before the bill went into collections. That was in early XXXX and since then I have called multiple times to get my account current, all the while paying my new lower rate. Still there has been no movement on it and I am reaching a point where this unpaid bill will count as a negative mark on my credit score. I want to be able to hold XXXX XXXX accountable for the bad customer service and for threatening my financial health. I filed a report with the XXXX, but they said they had no recourse with a government agency like XXXX. Please help!