Interest Rebate on Personal Loan

Two years ago, I have availed of a personal loan from a bank. Payment for the monthly amortization is deducted from my company. Early this year, I have resigned from that company and issued post dated checks to the bank for the outstanding balance of my loan. I have issued 13 checks, 4 of them have already cleared. In short, my loan with the bank is updated.
Just today, I have followed up from my company, my last pay. I was informed that all the proceeds of my last pay will be applied to my outstanding loan with the bank. I have called the bank and asked them why would they be asking for my last pay when I have already issued them PDCs to cover for my outstanding loan. They have even insisted that instead of a semi-monthly payment, I issue a monthly check which I did. They say that they will be calling me later today for further clarification.
Question : Is there a law wherein it indicates that should a loan be paid even before its maturity date, outstanding interests should be considered as rebate? I am willing to use the proceeds of my last pay to pay off my loan but only for the outstanding balance as of today, excluding the interest. I do not understand why I should be paying for interests that would have incur until next year.