Hello,
I recommend you first delete the nulled version of the theme completely, as it can cause security and functionality issues.
Then, download the recent version of the theme from the Themeforest account and go to Appearance > Themes > Add New > Upload Theme and activate it.
Navigate to WoodMart > Theme License and enter your purchase code to register and access updates.
Note: Always create a full backup before making theme changes.
Best Regards