Hi!
You wanna an automatic response software for Instagram and Messenger, and I can help you :-)
Facebook allows developers to create their own APIs (application programming interface) to interact with their services, which is the same, it gives us the ability to do what you want. That is very easy to implement and it doesn't require any cost, the only thing that is needed is an "access_token" and done. In the past, i have made similar products (not only for messenger and instagram) and I have the experience to do it. Obviously, if you wanna hire me, we can talk about that and give you a more detailed roadmap ;-)
Sincerely, Enrique Mora
Happy day!