Product: Student loan

The problem that I am having began when my loans were transferred to the new provider- XXXX ( XXXX XXXX XXXX ) in XX/XX/XXXX. At the time of my monthly payments my private XXXX loan had been transferred already so I made that payment through the new provider- XXXX ; but my federal XXXX loan had not been transferred so I made that payment with my old provider. 
In XX/XX/XXXX I paid my federal XXXX loan through my previous provider for the amount of {$50.00} as this loan had not yet been transferred when I paid my loans that month. When that loan was transferred to XXXX, XXXX was unaware of that payment for some reason, and listed that loan as having an unpaid payment for XX/XX/XXXX. They later became aware of my past payment of {$50.00} but have not applied that payment to any loans. 
In XX/XX/XXXX I paid my private loan on XXXX 's website for a payment of {$68.00}, as I had already made my XX/XX/XXXX payment for the federal loan on my previous providers site. XXXX split this payment which was supposed to be only for the private loan, and instead split the payment between the two loans ( as they did not apply my {$50.00} payment made to my previous provider ), hence making both loans not paid in full. I knew this payment of {$68.00} was more than the owed balance on my private loan- with was {$55.00} for XX/XX/XXXX but paid it to stop the delinquency status and emailed XXXX  to solve this problem. 
In XX/XX/XXXX I paid {$100.00}. This amount was supposed to be split between the {$50.00} for the federal loan and the remaining balance due on the private loan- since I had over-payed on it for the month of XX/XX/XXXX. 
XXXX is currently aware of the situation and have sent several apology emails about the situation and on XX/XX/XXXX I received an email stating that my loans will be reviewed and the amounts can be reapplied which would take 10-15 business days. However, I continued to receive messages stating that my loan was delinquent and that if I do not pay it they will report my delinquency to crediting agencies. This is a problem for both me and my cosigner. I have emailed XXXX multiple times since as it has been longer than 15 business days, and have had no response. My account still shows up as delinquent and they payment amounts are still incorrect. Furthermore, I have continued to receive messages about the delinquency and that they will report it to crediting agencies. 
XXXX has stated in an email that " you have paid {$210.00}. Therefore, you appear to have paid enough to not have any substantial delinquency if these payments are applied in the best way. " I am still awaiting the reapplication of my payments, but fear that my delinquency will be reported to crediting agencies unjustly. I fear this can affect both myself and my cosigner. Furthermore, I have been trying to solve this issue for three months already and have been unable to do so. 

In addition, I made payments on both my federal stafford loan and the XXXX loan every month on time for over six years with my past provider without changes to my interest rate. My loan has been changed over to XXXX for three months and they have already increased my interest twice- two times in three months. 

I would appreciate any assistance you can offer to help resolve this issue. I just want my loan to no longer show up as delinquent as I have made all payments. I want XXXX to remove the delinquency status of my loan to ensure this is not unjustly communicated to crediting agencies. 

Thank you.