Private Bus — amount not refund

I have booked my ticket in national travel bus on 7/8/18 from surandai to chennai. Due sudden dead of DR. Kalaignar(M. Karunanidhi former chief Minister of tamil nadu). So the travels service where stop the inform as that that the service is cancel and your amount will refund. Till now the did not refund the amount we have called the travels the did not respond and take any action about this. We have called them and told the did not take action and not yet refund the amount.