How to oppose auction under Indian SARFAESI act by third parties?

A lawyer sold us flats in a bldg. (group houses) constructed with a Bank loan in 2005. The property was charged to the bank under UnRegd Equitable Mortgage. Without any knowledge of the said mortgage, we had subsequently purchased the flats during 2005–07 duly registering our sale deeds, since there was no encumbrance on the property in Govt land records. Now Bank brought property to auction for default by borrower under Sarfaesi Act without any intimation to us. Please clarify the following: 1. The bank loan & UREM were dated 22.01.2005, Demand notice u/s 13(12) rule 3 was issued on 16.02.17 & possession notice u/s 13(4) rule 8(1) on 05.09.17. Knowing well that we are bonafide purchasers of the flats in the building, the bank had not served any notice to any of us except putting up notice on our bldg. The bank had not taken any action on the borrower for 12 years, even though the borrower had alienated the security by sale WITHOUT repaying the loan. 2. As unregd. mortgagee, is the bank not duty bound to periodically verify the encumbrances on the same to safeguard its mortgage rights, especially when sale proceeds were not reflected in Loan acct.? Had the bank did so, bank should have initiated criminal action against the borrower long back. Even otherwise, the bank was aware of the sale of flats but did not take necessary action so far, exhibiting negligence and conniving with borrower to the detriment of subsequent bona-fide purchasers? Whether we have any ground to proceed against the bank on it's failures? 3. If we file a petition in DRT for a stay of the sale, what will be the further course. Whether we can seek any permanent injunction on Bank from proceeding with sale of the property or whether we can claim a legal title to the flats purchased by us in preference to the bank? 4. We are informed by some experienced people in these matters that the bank's right in this matter will be UPHELD by the DRT, but we may be asked to pay bank dues by extending time by say 2 or 3 years. Is it so? 5. Whether UREM was NOT barred by limitation of 12 years? In such a case or even in other aspects, how to know whether the bank had initiated SARFAESI proceedings with due right or not? 6. Despite all this, if we clear the bank loan, whether we can get a clear title to our flats legally and the right to recover the said amount from the borrower? 7. If all present owners of flats do not unite, whether the willing owners can proceed together in the matter for safeguarding their rights? If so what will be reliefs/remedies applicable to willing owners vis-a-vis unwilling owners? 8. What will be status of the 2nd and subsequent owners of flats in the above dispute? Whether they can join other original flat owners against bank/borrower? How can they get remedy against the original/subsequent flat owner ? 9. If the bank auctions the property, how the auction surplus will be appropriated by the bank