Author collaboration issue. Need advice.

Hi everyone!
We have agreements with another Themeforest author. He has developed and is currently selling WP Theme based on our HTML template.
According to our agreements he should transfer 40% earnings from theme selling.
All was fine and the agreement was performed up to 2016 February. From this time and till now we didn’t get our profit from him. Current indebtedness of this author is over $2000. He ignores our questions about terms and agreements. We don’t get replies on our e-mails.
Envato doesn’t solve the issues between authors.
Was someone in same situation? Your advices will be appreciated.

Envato doesn’t solve the issues between authors but need to act on DMCA.If you have original design on your profile page or any other proof then you should place a DMCA takedown notice,item will be suspended.