Could it be possible to login to your website and debug this issue? You can share access data in the private field.
I have the same problem.
I bought Jevelin years ago and suddenly, my website is throwing up error codes and telling me that the theme is not activated. I have inserted the code a number of times but it is saying the code isn’t recognised.
This feature was requested by theme users as a way to validate that the product copy is legal and to receive automatic theme updates.
We have fixed this issue for most of the users, so if it would be possible to login to your website (you can enter access data in the private information field) we could try to debug it and most likely fix it also for your website.