Redbus — Not go to boarding at proper time so bus started going without taking me

As i have booked ticket for my travel from Kelambakkam, Chennai to Pattukkottai. Because of redbud last min cancelled trip as same travel, I have booked hurry to other travels bus for same destination . Due to some personal reasons I have been late to the boarding so bus taken away from boarding spot, so now as bus going without taking me, I ask driver ur late so I taken he told, I need refund please take action
Regards travels deltaking travels .