Is buying gold from an auction at a very cheap price, as a result of the bank selling it due to the mortgagor's failure to pay, permissible or forbidden?

It is permissible to buy gold from an auction under two conditions: First, the purchase must be hand-to-hand. A certified check, direct debit from an account, and a deposit into the seller's account are all considered equivalent to physical possession. Second, the bank's sale of the collateral must be legitimate. This occurs when the debt matures and the debtor refrains from repayment. If the debtor grants permission, it is permissible. Otherwise, the ruler compels him to sell, and if he does not comply, the ruler sells it. The ruler may delegate someone to conduct the sale. If the state's regulations authorize the bank to sell the collateral, this is equivalent to permission from the ruler. It is stipulated that the bank must sell the mortgaged item at its fair market price, not for less. Therefore, it is not permissible for the bank to sell gold significantly below its value, nor is it permissible to purchase from it, due to the invalidity of the sale and the unlawful appropriation of the mortgagor's wealth.