Thank you for the post, and I'm sorry to hear about the issues you're having with your system.
The mute button on the Soundbar can only be engaged/disengaged using the button on the Soundbar. If the button isn't responding or the microphone disables itself, it means that there may be an issue with the touch sensor on the system. I would recommend contacting your local support center via phone to arrange for a replacement.
Please let us know if you have any other questions.