Hi,
I can assure you our themes are indeed working, they power thousands of users.
If you encounter an issue, please report back the error your get, any related error messages and also any screenshots of the issue.
Make sure when you are overwriting the “nulled” theme version you are not actually merging files. You need to delete all old theme files and upload the new files overwriting everything that was in the “nulled” version.
Thanks.