partition suit for fathers bank account money, flats and land

My father died intestate on 20th April 2021 due to cardiac arrest. My father has a joint account No.30167126259 in SBI bank Barhalgunj Branch Gorakhpur and in which my step mother is joint account holder. Now my step mother is not willing to share the amount held in my late father's account between all the legal heirs of my family which includes my step mother and three brothers. So under these circumstances I requested the branch Manager SBI Barhalgunj Branch to freeze the account or make it dormant till the time my step mother not agrees to share the amount between all the legal heirs and provides consent of all the legal heirs to do so. In this regard my middle brother Moh Rashid submitted a letter to the branch manager but he refused to accept the letter (copy of the letter attached herewith) saying that the account is a joint account. As all the courts are closed in the month of May and June 2021 due to corona and lockdown in UP so we are unable to provide court order.