VERY BAD AND UNPROFFESSIONAL SERVICE

I have being paying my personal from my cheque account for more than a year, with out issue. This morning I made a payment and then saw that I have a smallish amount to settle. I tried to pay the exact settlement (to the cent). Neither the web or cellphone app will let me. The response is I am paying more than the balance. I have been transferred from one person to the next (for almost an hour). The last person I was transferred to, is in the debt review dept. The call just ended. How the hell am I supposed to settle this loan?!?