Automated AI Support for PHP Site

My PHP-based site needs an AI layer that can step in as the first line of customer support. The goal is for the chatbot to recognise routine questions, search our existing FAQ/knowledge base, and deliver a clear, formally-worded reply without any human involvement... (Budget: $250 - $750 USD, Jobs: AI Chatbot Development, AI Integration, API Integration, HTML, JavaScript, MySQL, OpenAI, PHP)