Auction time extended by an hour without prior notice by bank

I had participated in an auction recently to purchase a house. As per the notice given by the bank, the auction was supposed to be conducted from 4 pm - 5 pm with the auto extension of 5 min (provided if any bid is received within the last five minutes) till the sale is concluded. However, without any prior notice, scheduled auction time was changed to 4 pm - 6 pm without any prior notice. I was the highest bidder (H1) till 5 pm (Price P1), but later after 5 pm someone started bidding, and the auction went on. Ultimately I am the highest bidder now as well (P2). P2 is substantially higher than P1. Can I ask for the records and file a case asking to allow me to register the property at the P1 price? I had asked the manager for an explanation but was told that the other bidders did not get the login details and hence the auction was extended by an hour.