Hello AmélieFast,
Thanks for reaching Microsoft Community. We're sorry to hear about this issue on your earbuds.
In this case, please see Charge Surface Earbuds (microsoft.com) for more info. But if the light still no longer comes on, it indicates a potential hardware problem. At this point, your earbuds need to be repaired or replaced.
For further assistance. kindly contact our support via Contact Us Microsoft Support from (6AM-10PM PST) to seek exchange options for your earbuds. You can also contact them via phone, see Global Support Phone Numbers.
I hope this helps.
Best wishes,
StevenK