Question about Bose QuietComfort 35 II

Hello, I have had the headphones for a few months and recently they have not been working properly. At first they always connected to my devices, but the sound then didn't come or only directly from the device. I was able to solve this problem by disconnecting them completely and pairing them again. The problem at the moment, however, is that the noise-cancelling no longer works. When I press the corresponding button, nothing happens. What can I do?