National Highways Authority Of India [NHAI] — Fastag cancellation related

Sir, i have a fastag from sbi. i have sold the vehcile(bus) with sbi fastag now, i had a contract with the bus in education instituion and the bus is registerd in name of the principal of instituion, when i try to cancel the tag they are asking me to provide a canceled check in the name of rc owner (i.e the principal) and a canceled check cannot be produced as it is a designation and presently i am not the contractor there. Even with repeated emails they have only one response to reply "pls contact crm portal". when i registerd a complaint in crm portal there is no update on it and no ticket number is issued to me. Now the vehcile is sold to other person and he runs the vehcile and because i cannot cancel the fastag i am forced to pay the toll double charges, even while mentioning all these the sbi fastag has no lead to provide. Before hand i have canceled 4 of my vehicles in this similar manner and i faced no issues on it giving the canceled check in my name.
[protected]@sbi.co.in
[protected]@[protected]@sbi.co.in
[protected]
these are the two mail id and number i have contacted and its been a month i am back of this, pls do the needful to cancel my fastag