Bad practice

I bought a GoPro Hero Session from Cape Union Mart on the 25th of November 2017. When I started to record with it I found that it got extremely hot. I had to switch it off after 45 minutes of recording cause it got so hot and I was afraid something bad might happen. After leaving it to cool down completely I tried again and again it got so hot after 45 minutes recording I had to switch if off.

I took it back today the 3d of December 2017 wanting a refund sins there was obviously something wrong with the product. And it was still under Cape Union Marts 7 day money back caurantee. But They refused to refund me.

They insist on sending it back to GoPro and wait their report before refunding me or even replacing the said item.

I am a Cape Union Mart client not a GoPro client, I bought the said item from Cape Union Mart under their money back guarantee not GoPro's. I certainly do not understand why I can not get my refund on a product bought from them that is not working the way it should. And this will surely make me think twice before I purchase anything from them again,