Unfair Banking Practises done by bank

I’ve availed a home loan of 20 lacs in Jun 2011 @ 11.75%/240 installments/EMI 20,700. In year 2013, I couldn’t pay EMIs for 3 months and my A/c declared as NPA. Bank send notice under sarfaesi act. I refunded all the outstanding EMIs with 2 % penal charge as per loan agreement in one lumpsum in 4th month through RTGS and matter settled. Since then I have been paying EMIs without any failure. But on last week,(after 4 years and 3 months) I got a tele call from bank that Rs 82K is overdue on my A/c. When I visited the bank it is informed that my loan a/c was re-phased and EMI was revised wef 01 Mar 2013, whereas I was not informed with this till date. Bank was placing the cheques which I had submitted time to time even last month also. They tell EMI was 22,800/- wef Mar 2013. Further, they say If I pay Rs 9500/- to switch over to lower interest rate whereas it was a flexible rate H/Loan.