whatsapp chatbot and sender

I need build structure for whatsapp messaging Need expert developer in this field. Need software for creat hash channels. i need creat a simple autoresponder with 4 or 5 pre loaded small texts, but this chatbot need work with hash-channels. need creat a sender who using hash channels , suporting broadcast system and directly messages. Please only developer with a lot of experience in this field. Need reduce costs. i provide all needed for this work. Who is able to show ready project we can discuss the terms, Thanks!