Can't register and update my Avada Theme

Need to update Avada theme for client’s site. Their current version is 3.9.1. I purchased new version. Put in our Themeforest username, purchase code and token. Keeps telling me there seems to be a problem. Can’t open a support ticket because you need to register product first. Do i need to use the client’s Username? Which they don’t have, because they had someone else build their original site.
Help! Thanks

Hi

username will be the theme purchaser account username. please check theme support docuemtation how to register the theme, hope you will get proper help there.

Thanks