Brand new sagging couches

Good day,on the 11 November 2023 I bought an paid for my Santorini 2 seater an Santorini 3 seater couch in Thuli cement color. Since receiving my couch,I have been to the store in Mall of Africa, called several times an emailed as well. My couches which is basically a month old is sagging,we have plumped the couching an turned them around but still it sagging. I find this very unacceptable as it was not cheap,we pay an arm an leg for good products an this is what we get. It is the 5 January 2024 an still no one has called to inform us when will the couches be collected an stuffed properly. Hiw is it possible for a brand new couch to be sagging. I would like a response to my query an I would like to know when will it be collected an properly stuff. If I am not entirely happy with the service I recieve I would like a full refund.