AI based VOIP development

I'm looking for a developer to create an AI based VOIP system. The main focus of this project is to implement natural language processing as a feature of the VOIP system. I'm looking for a full feature set, with all the bells and whistles that come with the AI feature. Additionally, there will be some existing systems that need to be integrated into the new VOIP system, we want to offer this service as an API, so experience in integrating existing systems is highly desired.
The idea behind is people can automate their inbound call centers and our AI bot will take all calls

Example system is flipcx.com