What sms or script to use to create a private correspondence?

Question

CMS

Hello, friends!
Please advise a system for creating a small "service" for users to communicate with the administrator face-to-face.

Answer 1

It is obvious from your question that you will spend a lot of time just deploying this "cms or script". Save yourself some time:
https://vk.com/im
https://web.telegram.org
https://web.skype.com