Product: Student loan

I went to pay my Navient loan payment on Monday ( XX/XX/XXXX ) and noticed the amount due had increased drastically, which was surprising because I have an email confirmation from XX/XX/XXXX that my income driven repayment renewal request was approved. I called Navient at XXXX XXXX to sort out the issue. After being transferred around and placed on hold for more than 45 minutes, I finally spoke with someone who explained that IDR had only been applied to half of my loans. I asked if this was an error on my part. Had I filed my renewal incorrectly. And the representative told me it was a processing error by Navient. He said he would place an expedited service order to get the problem resolved quickly since the due date was approaching. I check my account online over the next few days to see if the issue had been resolved, but it hadn't. So I called back at XXXX XXXX on Friday ( XX/XX/XXXX ). The person I spoke with ( ID XXXX ) said no order had been placed and nothing was set to fix the problem. I explained the issue I was having with IDR only being applied to half of my loans. She placed me on hold and when she came back, she explained that IDR was not applied to some of the loans because I had been paying extra on one loan ( XXXX Stafford - Subsidized ) for some time, trying to pay it off, but that had advanced its due date so far that IDR could not be applied to this loan. This confused me, because many loans were apparently affected by this. Not just the one I had been paying extra on. I asked why this would be the case, and the representative reiterated that IDR could not be applied to my loans when one of the loans had been paid so far in advance. She said she could change that loan, so the due date was no longer being pushed. So every time I pay extra on that loan, the due date will continue to be monthly. I said, yes, please change that, though I'm still confused as to why any of this would affect my IDR status. She put me back on hold to fix the issue. And when she came back, she said I should be all set. And that the IDR would take affect in 24 hours. And I said, wait, my payment is due tomorrow. How will that work? And then she didn't say anything. I thought the phone cut out. I asked if she was still there. She said yes. I said, did you hear me? She said yes. And then it was quiet again. I said, my payment is due tomorrow. What can I do about that if you haven't resolved the amount that's due? She put me back on hold to speak with her supervisor. When she came back, she explained that her supervisor would be handling this case and it should be resolved in 24 hours. But I was still free to make the payment online so as not to miss the due date. I was frustrated and asked her for a reference number for the phone call so I had some way to prove the call ever happened. But she said there was no reference number. Instead, she provided me with her ID. Once I was off the phone, I went back online to my Navient account to make my online payment, but the payment function gave me an error message. I haven't been able to make an online payment since. And my payment is due tomorrow. The function online just isn't working. So I can't even pay the bill that is still incorrect. I took a screen shot of the error message I keep receiving when I try to make a payment. At this point, I feel like I'm being forced to miss this payment, even though my bill is still wrong. I don't want missing a payment to affect my credit or to cause a late fee. But I can't pay if the site won't let me. And now I don't know what to do. I've called Navient. I've emailed them through the Help Center. I've tweeted at them. But I still can't make my payment. And I have no idea what to do next. This all seems criminal.