Case of 420 and defaimation against ank

I purchased a house on loan in Khoda ghaziabad. from a NBFC bank which has approved loan 2289000 lacs after all verification in month of december at rate of inerest 11.75 and started taking EMIs.they deducted 89000 for home loan insurance. And took 46000 as processing fee in its bank account. But did not issue the cheque by stating g that it will be during registry. On bank's saying seller done the registry but bank refused to give cheque in registry office stating that seller's one document is though is certified from court but not original n they want that too original. I asked that why they did not tell before registry. But banker did not not say anything and went. tion and will get back to me. I am under big pressure as i have already given 550,000 to seller and giving emi every month. Sometimes i feel to commit suicide as my name has defamed and i am being threaten by seller every day. Please suggest asap as can i file case of defaimaTion and 420 against bank and how ?