I bought headphones from a computer store. I wanted to activate 7.1 Surround Sound, I entered the code from the box - it says that it is invalid. Next, I entered the serial number of the headphones to receive an activation code. I received the code and saw that it was completely different, not like in the box, I was delighted, entered it. "Code is invalid. Please try again." I checked the correctness of the code several times, but I entered correctly. Help me please.