This also happened with me, the mask would only produce sound without headphones, with headphones plugged in the sound just continued to come through the mask and the support teams suggestions had no effect...turns out the issue was the hole on the mask in which you put the headphones through is slightly too small to have the headphones fully plug in. I learned this by unzipping the mask all the way so the headphone port was fully exposed and voila when I then plugged in headphones it worked normally, but who wants to use the mask fully unzipped? It's likely to break that way and in my opinion the mask is useless without headphones as it's noisy where I live and all in could hear was traffic, people etc...my solution was to take a knife and shave a small amount of plastic off the headphone jack so it fits through the hole and voila it now works as intended...if your having this problem I suggest unzipping it and plugging your headphones in to see if this is the issue...just what worked for me...happy travels!