Thanks for reaching out.
I'm sorry to hear you are having issues with your headphones. To clarify, you mentioned when you tried to sync them, do you mean the QC30? The QC20 is a wired headphone that plugs into your device, no syncing necessary.
In terms of troubleshooting, have you tried to update the firmware? This can be done by visiting this link on a computer.
If the problem persists, please get in touch with local support to discuss service.