Complaint regarding stained mattress from sundayrest.com

I ordered Mattress for my brother’s family from Sunday Rest (https://www[.]sundayrest[.]com/) and they delivered a stained mattress, for which immediately raised complaint with them via email with photo of the stained mattress. After many calls(Axxxxxv, nxxxxxxa from their team) and email to their customer care, they keep giving false promise that they will replace it, but its been more than a month, till now its not replaced. and now there is no reply to email or none answering calls in support number.