Product: Student loan

I have two loan accounts from the same university with Heartland ECSI, who is the loan servicer for XXXX XXXX. To briefly describe what has been happening, I'll try to use bullet points : - I removed autopayment function because system was not consistent with payments and would cause problems where funds were reversed. No notification of an issue with a payment until a week after the due date, which for me, lined up really well with when they report accounts to the credit bureau - If funds are returned to Heartland ECSI, misallocation of returned funds would cause one of my accounts to be 30-days delinquent and the other not to be, which is not possible, both accounts are on the same payment date. I make one payment for both A and B accounts. If you pay more than the minimum and funds are returned, it exuberates the problem. 
- Getting Heartland ECSI to correct the issue always is a multi-day challenge, sometimes years. 
- My credit score was wrong for a whole year in the middle of trying to buy a house, and I didn't feel comfortable buying a house because of my credit score. XX/XX/2022 incident was the second time the wrongful 30-day delinquency occurred and the credit bureaus did not rule in my favorite even though the first incident was corrected. After a year went by and many phone calls and emails with Heartland ECSI Supervisor, the delinquency was removed from my account. 
- I manually pay my accounts now ; sometimes the payment comes out next day, two days, sometimes three days. I'm not sure, but if funds are not available Heartland ECSI doesn't have the infrastructure to ping the checking account for payment again, but will wait, what I heard this week, five business days to see if the payment will go through before sending notification ; this is the only loan company I have that has this and won't ask the bank for the money again, but will also not send notification for five business days. 
- Returned funds from my payment four days before my due date this month, were miss allocated once again. When I checked my account on the XXXX it showed nothing of the returned payment, and I paid the random amount that was showing ( {$15.00} ) because I didn't want an issue. The next day on the XXXX a back dated returned funds transaction showed up for the XXXX and balance due of one and half times my actual payment. Account B showed a thirty day delinquency and past due balance equal to what I would have paid Account A that month, Account A had no past due balance. I paid again my normal payment, not the other half on the XXXX. Supervisors went back to find the problem after an hour of trying to convince them something was wrong and it wasn't me or my bank. Supervisors failed to explain the problem to me, but just that the accounts are in good standing now and the amount I owe is the daily interest accrual from my university ( {$11.00} ). I did ask for the ticket number they used to resolve the problem ( # XXXX or XXXX they told me two numbers ). If I didn't catch this problem before the XXXX a 30-day delinquency would have been reported, to which the supervisor said if that was the case, I could have just reported the error to the Credit Bureau ; I said that I don't want to have to get a correction made for a third time because of Heartland ECSI.