The way it works: your audience (i.e. followers) add you as a speaker on the redCall app, after which whenever you want to share with them a message in a personal way, you would go on redCall, record a voice message and press send. Instantaneously, your audience phones would ring as if you are personally calling them - exactly replicating a phone call.
Your audience would pick up and listen to your call. If they are unable to answer, your message will be stored in a voicemail section in the app. Whether users in your audience pick up straight away or listen to the voicemail afterwards, your call can only be listened to once.