Xperia Z2 :: Right Noise Cancelling Ear Bud Not Working?

I bought my Z2 in September and after 3 weeks the right earbud of my noise cancelling headset provided with the phone stopped working 100% of the time. By moving the jack connection it would come and go. This did NOT happen with my third party earphones and when trying in the Three store I bought the device in, my suspect noise cancelling phones worked with the Z2 on display OK.

My phone was sent in first time in end of Sept/start of Oct and after I got it back the issue remained and the service log showed only a flashing of the software happened.

I then contacted Sony Xperia support again to complain and was told all I could do was return the phone AGAIN to check the QA process used.

This happened and I returned the phone again. I received the phone back today and the issue still persists! Again no hardware changes made.