Home Loan recovery

Currently I have a loan with Kotak Mahindra bank (which was previously ING Vysya bank), there was a dispute in loan interest rates which was solved by ING at that time by dropping the interest rate and during that time there were a couple of installments were not paid. Post speaking to the bank representatives we came to an agreement that these installments will be taken care of towards the end of the Loan cycle or if there is a pre-closure. Post the bank change there were a few times when Kotak representatives called me for these installements and at all times my reasoning was the conversation that I have with the previous representatives to which I was all times told "We will check on this and get back to you", out of the blue I have received a legal notice from the company that tends to all the legal work for Kotak stating that due to failure of these installments I will need to pay of the entire amount of the home loan that is currently pending. **Post the enitre fiasca of interest rate change there has not been one Installment for the last 1 year that has defaulted, and now I am being legally held accountable for paying of the entire loan amount.