Razer tiamat 7.1 v2 headset is not working

Hello to all I recently bought Razer tiamat 7.1 v2 but when I tried to use it now it's just not working. I connected with USB along with 3.5 jacks and I can see the lights and everything but there is no sound what so ever! I took it to 3 local computer shops and they told me that its probably dead and I need to replace it but I have a feeling that it might be a setting problem. Any advice is greatly appreciated. Thank you!