NLP & AI based Email bot with workflows

We would like to add a feature to our existing product. This system will help our clients to generate business leads using AI and NLP. The system /app works just like a human assistant who reaches out to every single leads which is recevived via email and engaging each of them in a human conversation. The mailing system woul;d like to add Artificial Inteligence to read the content of the mail and have automated replies sent to them. Clients can set their Workflow to automate the entire process. Any past experience in the same field will be preferred. While quoting, send us the way you will handle it so that it gives us the confidence that you have understood the project and its expectations.