I bought a really nice carrier unlocked N10, good condition runs great etc. However I was not aware of the secret terrors of this device. The bootloader is essentially impossible to unlock without a token from OnePlus and I have only heard horror stories from those who have tried to get one.

I tried contacting regardless and, for some reason, entering the dial code for PCBA does nothing? The one for IMEI works fine. PCBA just clears itself with no further info.
They also want an invoice, which I have no idea how to get because, as I even mentioned in my email to the support team, I bought this secondhand. From Ebay. Would it be worth it to ask the seller if they still have an invoice? I assume they buy these in bulk so Im not sure.

I am already thinking of selling this to a non-techy friend so I can get back the money I payed for it.

All this to say; if anyone has any advice I'd appreciate it. Android version is 11, security update 2021-10-01, kernel version 4.19.125-perf+ (OxygenOS)