The agreement was between the bank, builder and you.The bank will pay directly to the builder and the builder will pay EMI till possession handed over to you.
Hence the default in repayment of EMI will be attributable to builder only, you can claim exemption from any action on this based on this subvention agreement.
The bank may proceed to initiate action under sarfesi aft on the property mortgaged wit them
You dont commit the repayment in writing and dont disclose your assets if you have any to the bank, let the bank initiate any action on their own which can be challenged because you cannot be held liable for a third party fraud in this connection.
If you probe deeply into it, you may find some bank officials also involved in this scam.
You may take a personal advise from a local lawyer on further developments