Edgars Cell phone

I bought a cell phone at Edgar's Blue route mall on Sunday 9th Aug 2020. Realised on Monday the 10th the phone cover is not sturdy and there is a fault with the cover, and within my 7 day period of returning, took it back on Wednesday the 12th ( only day I could as I am working), and they flat out refused to exchange the product. Claiming negligence, when there is clearly no marks on the new phone of a fall or damage, the phone was manufactured incorrectly and as the consumer who just spent R4000 purchasing this product, they refused to exchange it. Utter nonsense and unacceptable.