What to do if I accidentally threw away my razer blackshark V2 headset box with s/n and p/n?

What to do if I accidentally threw away my razer blackshark V2 headset box with serial and product number stickers? And now, I can't retrieve the activation code via email unless I register the device through the synapse app for the pro features be unlocked. That's a privilege for me. However, I did register my razer kishi (Xbox Edition) device but to no avail just a congrats email with no activation code even though the app says
"to receive an activation code to enable pro features you can either register a razer product or"... there is still a sticker on my razer blackshark V2 usb wire showing a s/n but when I use it to register it's invalid.