I understand you are experiencing issues with your A10 + M60 MixAmp. Here are a few steps you can take to attempt to remedy the issues.
Make sure that the microphone is down and in front of your mouth. Having the microphone up mutes the microphone.
Hard reset your Xbox One by holding down the power button until it completely powers off. You should be able to hear it click or shut down fully
Try using the provided inline cable and the headset on a smartphone and see if you can be heard during a phone call.
Make sure your controller has an unblocked line of sight with the console. Even a glass window can cause interference.
If these steps did not alleviate the issues you were experiencing, please go to the link below and submit a case. Let your agent know all the steps you tried and the outcome of your troubleshooting. It will help speed the resolution of your case!
Support Channel: https://www.astrogaming.com/contact/