I purchase T4S headphones and after a few months one of the speakers stopped working. After contacting the ebay seller they offered me a replacement at a cost and as long as I record a video proofing the issue. I accepted paying the fee and recorded the video, after some time I received the replacement headphones. After some time, the replacement T4S headphones also presented the fault where one of the speakers stopped working. I have tried contacting Bluedio support and the seller but no response this time. I was under the impression that this was a quality product however unfortunately that was not the case since the headphones and the replacement both presented the same issue after a few months only with minimal use.