Hi
I am now experiencing the same issue and have tried nearly all the ways you mentioned!!
The only difference is that: it happened to me on the day 1 when I unpacked it from the box!!!
Unfortunately it was already 3 months after i have purchased it (yes, it was purchased together with Surface and i have other earplugs, so i didn't bother to unpack and use it right away).
And it seems i cannot request a new one, as there is no such button like "return or request a new one" on my overview when i log in to my Microsoft account....
i tried to contact Microsoft through phone calls, but it never worked.
This is such an unpleasant and frustrating experience!! i cannot even use it for one full day and it's broken!!!
If anyone knows how to contact Microsoft or has any advice about what i should do, please please let me know!
: ( .....
and by the way: i have called the Netherlands support hotline like 100 times, and every time, they need to redirect me +5 times to the right contact, and there was once, after redirecting for many times, the person just who seems to be the final right contact just hang up the moment when he picked up the phone, and i couldnt even hear what he said....
so so so so so frustrating. i used to think Microsoft is a good customer-focused company. But it seems it is not the truth.
Jing