Product: Student loan

XX/XX/XXXX- I am currently under an IBR ( Income-Based Repayment ) plan with XXXX   XXXX. I have been in an IBR plan for about the past 4 years. Upon logging into my online account yesterday night ( XX/XX/XXXX ), I noticed that there was about {$2000.00} dollars subtracted from the " unpaid interest '' in my account and about {$2000.00} was added to the principal balance of my federal loans. My " normal '' principal loan balance was about {$35000.00} and now with the {$2000.00} added it is {$37000.00}. I could not understand why there was about {$2000.00} capitalized onto the balance of my loans as I am still in a " partial-financial hardship '' and I have never left the IBR plan since starting this plan in XXXX, so any unpaid interest should not have capitalized. 

I contacted XXXX  XXXX for an explanation. Upon being transferred 3 times, I finally reached an " Account Specialist '' ( Employee ID # XXXX ). This representative explained to me that XXXX   XXXX  made " adjustments '' to selected accounts in which capitalized interest was previously not calculated properly. When I asked why my account had an adjustment made to it, he explained to me that it could have occurred because I switched payment plans ( Which I have not, I have stayed in the same IBR plan for 4 years and re-certify every year ). This representative could not give me a definitive answer as to the reason this adjustment was made. His best guess was that I somehow switched IBR plans and interest that should have been capitalized at that time was not, which is why it was being " corrected '' now. This representative stated that a letter was sent out detailing this adjustment. I had not received any letter from XXXX XXXX telling me about any adjustments that were going to be made to my account. 

Upon speaking to a supervisor, I asked again why this adjustment was being made. She said that her guess is that a miscalculation could have occurred in XXXX when I went from forbearance into an IBR plan, in which interest was capitalized. She stated that the amount of capitalized interest in XXXX could have miscalculated and was just corrected by XXXX   XXXX in XXXX. I don't understand how an interest adjustment was miscalculated in XXXX and now apparently " corrected '', 4 years later. I can not understand how there was a miscalculation of {$2000.00} when I did not even have {$2000.00} of interest accrued on my loans in XXXX. This supervisor could not give me a detailed explanation of this adjustment, she stated it was a new " complex issue '' and that she did not have more information on it. This supervisor did state she would attempt to send me a letter regarding the " adjustment '' that was made to my account. 
This " adjustment '' was just made within the past 3 to 4 weeks. I was unable to get this issue resolved  with XXXX XXXX and I find it suspicious that {$2000.00} was capitalized onto my loans without any prior notice to me and without me being given a definitive explanation as to why this adjustment occurred. If a student loan company, like XXXX   XXXX, can arbitrarily add capitalized interest to your account without providing evidence of prior miscalculation or explanations, what is preventing them or similar companies from doing the same thing again, resulting in more interest payed by borrowers.