REGISTER ISSUE

Return it, these may be fake.

Get them from legit source like razer.com

my headset not fake 

Yeah, everyone tells the same.

Return it as new peripherals never come registered so you have been scammed.

Believe me, the headset is original. Why would someone add all the Razer logos, use the same materials, and attach all the contents of the box to sell it at the same price as an original headset?
The serial number cannot be fake, as it matches the one under the ear pad.

If the headset has been opened before or used and repackaged, is there a way to register the headset?

Believe me or not it's not a problem to copy serial number from original headset and stick it both on the box and headset. it's not a problem to copy a logo, box, stickers and so on.

Unfortunately some counterfeits are really well done and sometimes it's not easy to catch this.

That's why it's the best to avoid all Aliexpress, temu, lazada, emags, 3rd party sellers on Amazon and so on… unfortunately heard that some small local shops are also getting peripherals from Aliexpress etc.

Still I'd return it ASAP and get it from official source (Razer.com)

ok thank u
 

The last question is, does the original headphone actually contain 7 speakers inside or just one speaker that simulates 7.1 sound?

One and it's virtually simulating 7.1 via Surround app.

ok