Ionic videocalls and chat

I’m making an application in Ionic 3 to videocall and chat but I don’t know what plugin is good. I’m trying with Cometchat but the support is very slow, the iOS sdk doesn’t build, and the docs are bad written. I want to use a plugin to avoid various problems and cut the developing time. The app will have lot’s of users (like 1000-5000). It would be great if the service is cloud hosted maybe with monthly subscription