Build me a chatbot for Whatsapp

I have a request for a rather peculiar Whatsapp bot. I offer a service with which users can ask our assistants for help with anything. By choosing the help category and then writing the question, the user must be put in contact directly in the bot's chat with our personal assistant. The service must be offered through a monthly payment and there must also be a part of the bot dedicated to assistants, with which they can chat with the user and manage all requests.

Features required in the chat:
• Subscription subscription
• Login and account management