Myntra.com — order not delivered on promised date

I have placed order on myntra on 28th sept 2019. The delivery date they have given is 4th october. But till now itmes not deliveres. I am keep complining this. But no repsonce from mynta. And for one return request also i am kepp gettong messages like pickup failed due to reschedule from customer. But i did not reschedule any pickup. How could they sent message like this. If they are not able to deliver and pickuo the items why they are doing this type of business.