Section 138

Dear Sir, I have purchased a flat and opted loan from bank. It was clearly discussed with builder that till possession builder will pay emi. However initially builder paid emi through my account and further @1 year paid directly to bank. After sometime they started defaulting emi and while asking they proposed to surrender the property since that was sold to someone else also. I realised and surrender the flat. Builder gave me letter defining that now onwards all liability yltowards loan with builder. The same was submitted to bank and bank didn't have any recipes and bank produced my security cheque which was bounced. Now bank filled case against me for 138. We approached builder but he is not giving proper answer. 138 proceeding going on and do not know what is going to happen.. I have gone through the document and there is no clause where builder will pay emi till possession but I do have the following documents:- 1- Loan account statement which shows the emi payment by builder. 2- My account statement indicating recipes of emi amount from builder and deduction by bank 3- Surrender letter and acceptance by builder that all liability towards loan will be builder. 4- Tripartite agreement which state that in case of cancellation or surrender builder will inform to bank and refund the loan amount to bank Please advise what to do. I am very much depressed. Thanks