How to handle if bank send the notice by threatening cheque disho

Hi, Have taken home loan in nationalized bank through the builder 2 years before. As of now the possession of the building was not been taken due to incomplete work in flat and by intervention by local political people. Bank has been following up with me and the builder. Till December builder was paying the few emi amounts after that he didn't pay. 1 year before have given the bank in writing that i want to surrender the flat to bank. One week before have received the letter to my resident and also to my office from advocate stating that loan account has gone to NPA on May 2017 and i need to pay the entire loan amount with in 3 days, else bank "Bank has also taken a decision to initiate criminal proceeding under section 138 of NI 1881”, against the dishonor of Postdated cheque". I have never received any letter from bank stating NPA. Have met the bank people after received the letter and they are asking to pay the pending emi or to clear the issue with the builder. Have asked them time, they have asked to take time to settle it, but when asked for how long the time is, they didn't give the exact the date or period. In the letter sent by advocate they have also mentioned about SARFAESI Act, 2002. Please advice me how to proceed to avoid any criminal or legal action against me. As the bank people also confirm that the said property has issue with the local political people and on this ground im not willing to take up the flat. Thanks