If you made sure the connection is tight and the issue is not with the device you are using, contact their support or place you bought them to return or exchange them.
Those have a 4 pole connector, are you using that directly to a laptop or something with a single combo jack or are you using some adapter with them?
You should try resetting the settings once again. And if this problem is still there, then my suggestion would be that it would be okay to return or exchange by looking at this policy. But if it is not under any policy, then you should communicate with the customer care.
You can check the mic with some method that they can find out whether it is working properly or not. With a similar microphone problem, I found a site that test online mics. Out of that, I would like to share my favorite site with you https://mictests.net. The site also shows Mic sound wave. And keeps the test secret by keeping his information secret.