Airindia Express - AirIndia Express not refunding the Cancelled flight charges

Dear Sir/Madam, I have booked a flight with Airindia express on May **th which was cancelled due to COVID-** situation and the company have asked all customers to reschedule the flight with no change cost expect fare difference which applicable have to paid and also this option is given for customers only till September. As a customer when trying to do the same, thier website is not provided with future scheduling options and also after doing multiple follow up these people are not responding back for the refund of the amount. Request you to do the needful by taking this forward.