Full stack developer required.

Required full stack php developer. We have a business networking project on PHP and CodeIgniter. We required a developer who has a good knowledge of core php, oops concepts and knowledge of codeigniter framework. We will only pay the requisite amount after completion of the project. The project was purchased from itechscript few months back. We need to integrate a "Call" feature. Connections can call each other like Whatsapp. Also some design needs to be changed.