A banker is having the right of general lien and can exercise such right to keep the amount of balance available in the account of such guarantor and borrower. The presumption is that you have already been notified about the default status account of your friend's account. Contact the local advocate and negotiate with the bank and at the same time bring pressures on borrower through common friends.
Yes, the guaranteer is bound bu his guarantee. But the this could be enforced only through the due process of law; the bank cannot take law into their hands. Please try to ascertain the facts of the steps taken by the bank before 'seizing the account'. You canbring the matters to the notice of the Banking Ombudsman if the Bank is at fault.