Product: Student loan

My complaint is Navient increased my payment amount and extended my loan terms without my approval. I have contacted customer service 3 times, spoke with XXXX managers and my issue is still not resolved. 
In XXXX XXXX, I noticed my payment amount was increasing. My standard payment was XXXX per month for XXXX terms starting on XXXX/XXXX/XXXX. Estimated payoff date was XXXX/XXXX/XXXX. I have been making monthly payments since XXXX XXXX and have never had any issues with XXXX XXXX or Navient until XXXX XXXX. I have always paid my payment in the month that it was due even when it was late. Now due to the increase in my payment amounts, my payment has exceeded the 30 days. 
I contacted Navient in XXXX XXXX to discuss the purpose for my payment increasing. I was informed by the customer service representative that I was in a flood zone and due to the natural disaster in my area my payment changed. I explained to the rep that I was on the West coast and the hurricane was on the East coast. The representative informed me that a mistake was made and that she would correct the error. I paid the increased amount and expected my payments in XXXX to reflect the previous amounts I had paid before XXXX XXXX which was {$120.00}. In XXXX and XXXX XXXX, I had the same issue. Therefore I contacted Navient again on XXXX XXXX, XXXX and requested to know why my payments kept fluctuating. The representative stated that I had requested a forbearance which is why my payment changed. I reiterated to the representative that I never requested my loan terms to be changed nor agreed to any forbearance and that I requested Navient to correct the error and to change my payment terms back to what I originally agreed to with XXXX XXXX in XXXX. I then spoke with the representative manager who stated that a forbearance letter was sent to me stating that my loan terms had changed. I informed the manager that I did not receive a forbearance letter nor did I request forbearance and that I was going to review my loan documentation and respond back. 
On XXXX XXXX, XXXX, I contacted Navient again to discuss the error with my account. I spoke with a representative who could not explain the payment increase. I read to the representative part of the last document that XXXX XXXX sent me dated XXXX XXXX, XXXX. I then spoke with the manager, XXXX employee # XXXX. XXXX informed me that a forbearance letter was sent to me was the reason for the change. I reiterated to XXXX that I did not request forbearance so I would like an explanation for the payment and loan terms changing when I did not request it. I informed XXXX that I have been making payments since XXXX and now that I only have about 13 months of payments to make Navient has decided to increase my payment and extend the loan term. XXXX could not explain the reason for the forbearance or who requested it. Finally I was told they did n't think I would be able to pay it off by the deadline is the reason they changed it. I believe that decision should be decided by me not Navient. 
I have been attempting to make the payments but as a result of the change ; I have been consistently late even past 30 days. Navient also increased the amount of the late fee. I do n't understand after all these years of making student loan payments why would Navient suddenly decide to change the terms, payment amount and late fees. I am requesting some assistance as to why this was even changed in the first place and to refund me the late fees for the increased amount and to change my payment back to the original terms.