Samsung - defective product dekivered

I had placed an order with Samsung Shop App for an S** Plus which was delivered on **th of September. The phone was defective and had issues with display. I had visited the service center near me and was asked to surrender the phone for approval. Later they raised a DOA and returned the phone sealed and closed in their cover. I had been trying to contact Samsung regarding the issue and wasn't of any help. They never gave me an update. I couldn't place a replacement because the order status was not updated on the Samsung Shop App which they updated Post **days from delivery. Now they have scheduled a reverse pick up and no replacement option is given. I had been trying to contact the team for the past two weeks but the customer care executives never forward the calls or help me connect with the technical team nor they gave me a call-back.
I don't understand what's next because of the negligence to a customers concern. For a mistake that's ***% Samsung, I had been suffering for so long and I don't deserve this for purchasing their product.
I have a sealed phone and a phone cover which I am unable to use. Since there was delay in the delivery of phone cover, I had to buy another cover and a screen guard which now is useless again.