As said, then i would ask Steinberg support. They must keep the codes somewhere based on your dongle code. If you have'nt registret your dongle at Steinberg, then it might be a problem.
Also i don't know if Arturia actually just ask for your dongle code, if that's the only code to be seen on the dongle. You can ask them too.
Keep in mind that anyone can have the software, and anyone can find a dongle. Having the software and the dongle is in it self not a proof, that you own a application. Somehow you must be connected to the software.
Your old accounts i assume must still excist. I would believe a account can be found, if you can give enough valid informations about it. But even then you must proove you are the person behind an account with valid informations.
As you only have used the eLicenser code then this perhaps apply:
https://helpcenter.steinberg.de/hc/en-us/articles/206530504-USB-eLicenser-Details-Tips-and-TroubleshootingAmong other things you can read this:
"Please keep in mind: Licenses stored on a USB-eLicenser represent the entire value of the corresponding software!
Make sure to register your products and/or the USB-eLicenser with the respective manufacturer and keep in mind that losing an USB-eLicenser can mean losing the software!"
If you could be connected and validated to your original Arturia account somehow, then i can imagine it's another matter.
Good luck.