Sleepwell — Newly bought mattress has sunk in

I bought Aadhar Super queen size mattress (on order) from Bhattkoti Furniture Shop, Dehradun on 20th Jan 2023.

After 10 days only, I observed that the mattress had started to sink in. I called the shop owner who told me to complain to Sleepwell directly.

So, I called the customer care of Sleepwell company on 2/2/23, after which I received a call from Mr. Deepak who asked me the details of the Mattress and its bill photo. He also asked me to send images of the mattress to him on watsapp. I sent him the images of the mattress as he had asked and he gave a complaint number, 244361.

However, within a couple of hours I received an SMS saying my complaint has been rejected. There was no resolution offered, no call back from Sleepwell.
Please see the images below and you can see how the mattress has sunk. I tried calling back on Mr. Deepak's phone but it was switched off.
I need immediate refund/exchange, as such service is not expected from a big company like Sleepwell.

Awaiting your response.

Jyotsna Rao