Ask HN: Modestly priced mobile SDKs for 1 to 1 customer support messaging?

I am trying to incorporate a real time messaging customer support system into my mobile app for users to contact me right away and chat with me in real time for any issues. This is a fairly common feature of many websites, I am not sure of the marketing name but it's that small pop up that allows you to instantly message a support person and chat with them without necessarily being registered. I would like something similar for my app. I have been googling but I don't think I am using the right terms because I am stumbling upon a lot of solutions which allow regular chat like person to person but not any for person to app master for support..

Ideally the solution would have a centralized access point like an app or web site for me to view and reply to my messages.. although I am not strict on it, I would also like to be able to receive a notification evertime a new massage arrives so that I don't have to constantly check for new messages.. is there such a solution out there, or will I have to implement this from scratch?