Myntra - Return request not fulfilled hence no refund

Being a pregnant I have to be calm and healthy but myntra gives me mental harassment. I ordered a product to gift someone at the starting of the month but the delivery delayed **days. I used to keep following up everyday. And finally I received a not good product so I placed a return request. The request was accepted on the same day. But no action taken against it from * days. Everyday I keep receiving message like pickup is gonna happen on that day and evening I receive a message like it didn't happen because I rescheduled it. But no delivery person called me regarding pickup. So how can I reschedule? I am calling myntra from a week regarding this issue. They raised a complaint and maximum with in ** hrs they sort out the issue. But I waited for ** hrs and called for update (as they don't have concern to update me after the mentioned time). They are asking me to wait for **hrs more. I am loosing my health and my baby's health because of this issue. I am badly want to take action on this.