A loan of 4000 million with the following conditions:

The loan is fully disbursed on 1/7/N.

Debt repayment plan: on September 8th , customer pays 2500 million, on November 1st customer pay the remaining balance.

Interest rate: 9.5% per annum

Interest paid with principal calculated based on the actual outstanding balance.

At the last repayment period, due to financial difficulties, the customer could not pay the debt and the debt was transferred to bad debt group. The remaining principal and interest payable were paid 2 months later. Calculate the customer's debt repayment obligation in the final repayment period. The overdue interest rate: 150% of the current interest rate. Penalty on interest for late payment 4%/year.