One year ago, I got an item collaboration offer from an author(Level 5). According to Themeforest terms I’ve created token for the author. This author got 2 WP items approved from my HTML5. I’ve received my share(profit) every month. But during the last 4 months, they didn’t send my share(profit). I’ve sent a lot of messages but they didn’t reply. In this situation what can I do?