Restructuring of EMI on bank loan

I received business loan from a private bank. Amount 30lakhs. Tenure 10years. 3years completed. up to date EMI paid. Due to financial commitment, I requested the bank for reduce the EMI amount by increasing the tenure from 10years to 15years.(maximum tenure 15 years for business loan in that bank). I send my request to bank branch, customer care, loan branch, regional nodal officer, principal nodal officer etc. But the answer received is '"Not able to consider your request."' Nobody give the specific reason for why they have not consider my request. What I have to do for increase my tenure period.