Flipkart — Nokia 215 4g DS 2020

I have ordered Nokia 215 4g DS 2020 on 24 July. Flipkart shows it should be delivered to us by 28 July. It is not delivered by time and it is automatically shows it will be delivered by 4th August. We have waited for the order and system is showing order is out for delivery since 28 July. I called customer service number and representatives are not giving us details for the order. I tried to cancel the order but it is not possible from my side or company side. They are just giving us 24 hrs waiting time every time.
Please make them to fulfill my order or make them to cancel and get me full refund.