Hello, I have the following situation.. I bought Blackshark headphones, and then I found out that there should be a code for the 7.1 sound program inside. But the card with the code is missing. I'm trying to register the device by serial number, but it tells me the device is already registered.. Apparently someone used the code, maybe the seller, etc.. I have the box and the receipt for the purchase... Please tell me what to do? I need your help.. I really want to activate 7.1 sound.. I love these headphones
