Themeforest takes tax for US customers

I am a non-us author from asia.but when a us customer buys my product themeforest deduct some amount from the item can I prevent it? Its really paining me.Before submitting tax information this fee was deducted from all users.but now form only us users.

You can start with this : TAX info
And there’re lots of discussions at the forum:

It depends on whether your country has an tax agreement with the USA about withholding tax on copyrights.
List of countries with US tax agreement

  • no W-8 form submitted = 28% tax on all sales

Countries without US tax agreement:

  • W-8 form submitted = 30% tax on US sales

Countries with US tax agreement:

  • W-8 form without TAX ID submitted = 30% tax on US sales
  • W-8 form with TAX ID submitted = benefits of tax agreement on US sales