Succession Certificate

My father passed away recently. He was receiving rent from the warehouse he jointly owns along with his two brothers. The ownership of the land wherein the warehouse is situated at, is jointly owned by my father and his two brothers. Now the warehouse comprises of 4 tenants. The invoice is raised in individual names of the 3 brothers and the rent is remitted to a Joint Account held by the three brothers. The payment advice being issued to the extent of each individual's share as per the invoice raised. Now since my father is no more, the remaining two brothers of my father, have decided that my mother be the nominee to receive the rent hereafter in place of my father. There is no objection by each family member of my father or the individual family members of the remaining two brothers of my father. We have prepared a Genealogical Tree/Family Tree for the family members of my father. Likewise we have also procured a Survival Member Certificate both issued by the Tahsildar Office. There has been a GST registration created in my mother’s name for the receipt of the rent. My mother’s name has been included in the E-Khata extract of the warehouse land, replacing my father. This is in joint ownership along with the two brothers of my father. The same has been submitted to all the companies along with an NOC from all the family members of the Three Brothers stating the acceptance of my mother to be the Nominee for my father to receive the rent arising from the warehouse. The above has been accepted by 3 out of the 4 tenants. However, one of the Tenant has withheld the rent to the extent of My Father’s portion as they require a Succession Certificate in my mother’s name. Only thereafter they shall accept my mother to be one of the land lords. However, they are paying the rent to the extent of the remaining two brothers of my father. Is the Succession Certificate necessary despite having produced all the above documents for the company that has withheld the rent? Furthermore, what will be the court fee for procuring the Succession Certificate?