We are sorry that you are experiencing an issue with your Marshall Headphones.
Before we classify them as defective, can you please check the socket of the device that you are using for any dirt or debris? Dirt or debris in the socket will prevent clear communication between the two devices. It may be necessary to use a needle to clean out the socket.
If the sockets are clear of any dirt or debris and you continue to experience an issue with the audio, please send an email to firstname.lastname@example.org or contact the support team through chat.