Seats not available after confirmed tkt

CHANGE OF BOARDING POINT :
If a passenger desires to occupy reserved accommodation from any station enroute, he would be permitted to entrain at any intermediate station he chooses irrespective of the distance from the starting station subject to the following conditions :

1.        A specific request must be made in writing at the station from where the ticket is purchased and reservation made atleast 24 hours before the scheduled departure of the train from the starting station.

2.        The Railway Administration reserves the right to use such accommodation from the originating station up to the station at which the passenger is due to entrain.

3.        No refund will be permissible for the portion of journey not performed by the passenger.

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CANCELLATION OF RESERVATION DUE TO LATE ARRIVAL OF PASSENGER :
If a passenger, for whom a berth or seat has been reserved, does not turn up up to 10 minutes before the scheduled departure of the train, the Railway Administration may cancel the accommodation reserved for him and allot it to the passenger on the RAC list/Waiting list accordingly on priority.

https://www.indianrail.gov.in/reservation_Rules.html

Now you cannot do anything against the railway.  TTC has rightly executed his rights by alloting the seats to RAC passengers.  It is your mistake not occupying the seats from your original boarding point.