Hardware Error Code 102-2613, Nintendo keep asking me for serial number of previous console I don't have

[KingToriyama]

Hello, I just recieve my console, since 3 hours I tried to connect on my Nintendo account and I always get this error code : 102-2613 with a message telling me that this Nintendo Network account has been used to another Wii U console, the one I selled 2 years ago, I got in touch with Nintendo's after-sales service and they ask me for the serial number of the previous system, which I don't have anymore, so since 2 hours it's an endless loop where they ask me the same information: IDs, serial number of the old system, birthday etc... What can I do ? There's really no way for me to unlink my old console account with the PC ? This sytem is a mess, I still remember formatting the console before the sale so there's no way it's still linked to this day.