Issue with Bank

Hi, I purchased a landlord share flat via builder in 2016 for 30 lakhs and applied loan with HDFC Bank. Bank has sanctioned my loan application and processed my loan. For the loan amount, total 3 cheques were disbursed by bank to landlord i.e(1st cheque of 20lakhs, 2nd cheque of 5 lakhs & 3rd cheque of 5 lakhs) and my total EMI is RS. 26000 for 30 lakhs. Recently i got a call from HDFC BANK manager and he informed me that last cheque of 5 lakhs issued in March 2017 was not cleared at all. I went to bank to enquire about this and I questioned him why bank has not approached me MARCH – SEP 2017(validity of cheque is 6 months) and why it took 7 years to approach me. I've been paying EMI for these 7 years without knowing this. There was no proper response from bank for all the concerns i raised. Bank has not given any written communication regarding this lapse in any form(written letter/SMS/email) from March 2017 to till date to me. There is no communication from Landlord also about pending 5 lakhs till date to me. Through some reliable sources & upon further investigation i found that bank made mistake from their end. They have mentioned wrong bank account number in the last cheque. Moreover bank is not extending any kind of support for the excess EMI I’ve been paying for the last 7 years. In such cases, what is the solution given by banks and what will be the impact on me as I’m paying EMIs for last 7 years. Should I approach my landlord for this. If I have to proceed legally on bank what is the solution. Should I take my landlord also into confidence and approach bank ? Kindly advise as I’ve lost so much of money due to the gap identified at bank.