Corporation Bank — housing loan

Address:

Na, 400092

I have taken the loan of 13 lakhs in the year 2004 period 25 years
After paying a loan for 16 years total amount paid 21lakhs the bank has increased my principal by 1one lakh which is now 14 lakhs. And when i asked for explanation the they say that whatever i paid till now was only interest henceforth whatever i will pay will be the principal. They are telling me that i have to pay total 40lakhs against 13lakhs. They are not ready to give me in writing anything.
For getting better clarity i asked for amortization schedule they denied me saying that they don't provide with amortization schedule in any circumstances its not there policy. Furthermore they are not providing me the facility of repo rate.
I tried calling customer service, branch manager and even zonal office no one is having any reply to my queries as how come my principal has increased and what happened to my emis which i was paying so far.
Please help me