yatra.com is a cheater and making public fool

I booked a ticket for my parents to travel from Jammu to Dehradun. In place of selecting 15 June, I selected 14 June.I want to modify my ticket. yatra.com is not allowing to modify the date of travel.They told me that you have to cancel the ticket and we will deduct 25%.Since travel date is far ahead, how they can ask for so much high cancellation charges?Why there is no modification facility allowed on yatra.com website?Such a website should be closed.In all the govt tour operator buses, they generally deduct not more than 10% and sometimes even a very nominal charges . We should never use yatra.com for any ticket booing as the company appears to make customer fool.They only want to earn money by making customer fool.