1. Even if you are the highest bidder and have paid the entire bid amount, since there is a stay granted by high court, the bank will not be able to furnish the sal certificate nor it will be able to take physical possession of the property until the stay is vacated.
If you are not willing to continue with this then you may issue a legal notice to the bank to either handover the possession of the property along with the sale certificate or refund the entire amount with interest within a time period that may be stipulated in the legal notice addressed to the bank.
2. Until and unless proper and prompt follow up action is taken by the bank, the stay cannot be vacated so soon, hence you may decide.
3. The borrower has already approached high court with some reason, and the court also has accepted the same, so the best option before you is to implead yourself in the pending case as necessary party to the case and vent your grievances and objections to the case filed by the borrower against the bank in this regard