Lost key and purchase information

[elcamarao]

hello! Can someone help me how to retrieve my trackmania 2 canyon key? I bought the game 10 years? ago and kept the installed, and wanted to transfer to ubisoft account. I have the maniaplanet launcher and can run the game there. It detects the game as bought and I can play online etc. but after contacting ubisoft (even after I sent screenshots playinng the game and the menus inside the launcher) they can only transfer If I have a key or purchase proof. I don't even remember where I bought the game back then.
how to solve this?
Regards,

edit: I have 2012 to 2014 file logs. don't know If it helps..