Purchase Code does not work, what to do when support for a theme is over

Hi,
I have purchased a theme in 2018 its called JupiterX. I have never used it until today. But the purchase code does not work. What can I do about it ? Support is finished long ago, but with a valid purchase code I should be able to get help for the activation, right ?
Thanks and best regards
Beat

It’s on the grey zone as the support period is ended, support may not be available.

You should’ve purchased the item just before you start using it but you can contact the item author for help.

Thanks a lot, I have contacted the author. Will see, what his reaction is…