MOHELA Student Loan Complaint

MOHELA Student loan department,

Federal student loan servicing Dealing with my lender or servicer Trouble with how payments are handled Georgia

I have been paying my loan servicer, Mohela, an extra amount each month to pay my loans off quicker. I sent them a letter directing their accounting department to apply money above and beyond the amount due on each loan to the principal of the loan with the smallest balance. Twice now they have misapplied funds and sent me past due notices in between statements. When incall about this they tell me it is impossible for their accounting department to keep my instructions and follow them. I think this is nonsense. Please look into this