Bank is sealing my flat

Hi, I have bought a flat in Mumbai and have paid 99% of the many almost 1 year ago and have a registered agreement with the owner. The owner has said that he will give the papers of the flat to me within 10 days of payment. One day we got a notice from bank that they are going to come and cease the flat with a court commissioner. The bank officials along with the court commissioner and police officials came to our house to seal it . They told us that the owner had 15 lakh worth of dues and if he failed to pay 4 lakhs on the same day when they came to seal the flat they would seal it off and if he paid 4 lakhs then they will give time till 30th of June. The person from whom I had bought the flat had paid only 2 Lakhs and the bank officials thteatened me to pay the rest of 2 lakhs so I paid them . While buying the flat the owner did not tell me that the flat is on loan. It is secured in the bank under the SARFAESI Act. The previous owner says he does not have the money to pay the bank. We have given him all the money only 1.7 lakh is balance. The bank is going to come and seal the flat in 15 days. What steps do I take so that I have the possesion of the flat and also get the chain of agreements from bank. PROOFS THAT I HAVE ARE:- Account statements, Share Certificate,Registered Agreement,Notary of 500 RS stamp paper on which the previous owner has pledged to clear the dues and make ste that our house is not sealed. Please give me your opinion as soon as possible because if the bank seals the house my family will come on Road. Waiting for your response. Thanks and regards, Zahid