Flipkart — Wakefit orthopaedic mattress

Hi
I ordered a wakefit orthopaedic mattress from Flipkart Order ID - OD[protected] on 21st September 2022 and got delivered on 29 September 2022.
The product was not helping me in alleviating the back pain and i had asked for return of the product to be pickedup within 3 days.
I had asked for return request for pickup and for refund amount of Rs 7619.
They have acknowledged the issue and they promised to take back the mattress on 6th October 2022.
It's not happening in spite of repeated phone calls, email so far and they have not picked up the mattress and also delaying the refund.