Ecsi review: Payment Transaction not Processed

I've submitted electronic payments for 3/15, 3/20, and two payments for 4/1/13. The first two payments were never processed, may loan is in repayment and interest is accruing. Automated phone service does not recognize my account number and pin, no such account exists. My school says they are a legitimate load service provider, but frustration as set in as they show no records of my attempts to pay them. Even if it shows a scheduled future payment, when I print it, it shows nothing but the balance, and no payment amount or date set. I'm getting conflicting information from employees there, one says to make the payment on the 11th, when the due date is the 8th. Another employee who has been there several years says that doesn't sound right. I'm not sure what my options are now as the due date is rapidly approaching. Is this a legitimate loan servicing company?