We are very sorry that you fill this way but:
1) If you build the site for your client and use the theme for his site and it’s activated using your purchase code from your permission and it’s in use it means that this license is transferred to your client, please, read the point 4 of the license policy about building sites for the clients https://themeforest.net/licenses/terms/regular
We can’t deactivate the license without informing the site owner because we didn’t see your contract with your client etc. As I can see that site has the tel number and email. Can’t you contact them? Do you want that we contact them with this question?
2) If you want to revoke your license then contact Envato support, please. We do not manage that moment. We just control using of purchase codes on client sites. We can’t revoke the license just from our side. Only Envato support is able to do that.
I have used other theme and in this kind of situation they help me out to revoke the theme license and your team is saying you can’t do.
Have you already faced such a situation many times? How many and with which themes?
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.