JBL T450BT on ear Bluetooth Headphones

I bought my son Bluetooth headphones on his Birthday to the value of R995. The product stopped charging midway into the year which I discovered after asking my son why he is borrowing my headset. I then took the headset back to the seller within the 12 month return period. I then got told that my warranty is void because I do not have a box. I asked the employee to show me the policy. They then read out terms and conditions on the back of the till slio which does not make reference to a box. I am not returning the product for it to be re-packaged and put back on the shelf as it is defective. I'm returning the product as it is a premium brand that should be honoured under warranty, the reason I purchased such an expensive brand. When I asked the employee if they had revived train8ng on how to deal with returns or if she could show me her work instruction or standard operating procedure for claims she had no idea what I was asking for and kept on referring me to the terms and conditions. I would like to encourage musica to support staff more in this regard. I left the headset with the staff member. She did not give me any form of proof that the item was submitted to her as a return I had to ask her to write something on a loose piece of paper as proof of handing it over to her. I then asked her to stamp it as well. It has been 2 weeks now and I'm still awaiting feedback from the seller. With the level of service I received I would be surprised if anything has happened as yet. How should I proceed?