Airtel - Overcharging

My name is Udit Monga. My late father, Mr Vipin Kumar Monga, was the sim owner of a Prepaid Airtel Number **********. His sim/mobile number (**********) was recharged for a period of * years worth Rs **** (****+****) in the month of June & July, ****. Soon after, my father Mr Vipin Kumar Monga passed away. The sim/mobile number (**********) was working fine till November, ****. On *th November, ****, out of nowhere, his mobile/sim number (**********) stopped working. The sim/mobile number (**********) was temporarily blocked on request at authorized Airtel Store on **th November, ****. On reaching out to the Airtel Store and letting them know about the death of the sim card holder, I was informed that the sim/mobile number (**********) can be transferred in my name but the recharge done by my father for the period of * years shall be cancelled/removed after the ownership transfer in my name & I'll have to make a recharge again to use this mobile number (**********). As it is a genuine & clear case of inheritance among blood relatives, it is only fair that the sim/mobile number (**********) must be transferred in my name along with the recharge validity of * years & benefits as per the plan chosen & paid for by my late father. Even after several email communications & telephonic correspondence, Airtel is unwilling to let me use the services of sim/mobile number (**********) which is already paid in advance. Kindly help me resolve this issue and instruct/direct Airtel to provide me a new Sim for mobile number (**********) alongwith recharge validity of * years & benefits as per plan chosen & paid in advance to Airtel With Ownership Transfer in my name. Help me fight this wrongful & illegitimate practise by Airtel of looting its customers by abusing the laws that are meant to provide fair & upright customer services. I'm not demanding anything extra, I just want my money's worth for the offer/plan curated by Airtel & paid in advance to Airtel.