Ring4 uses a very small amount of of you data plan. A voice call over IP uses around 500k/min, which is 100x less than min of a Zoom videoconference or watching a min video on youtube for instance.
If you are not connected to a Wifi network then Ring4 will use a very small amount of data.
Ring4 is VoIP (Voice over Internet Protocol) application that uses your data plan when you're not connected to a wifi network.
To understand how small of data Ring4 uses a voice call over IP uses around 500k / minute, which, for instance, is 100x less than a minute of a Zoom video conference or a minute long video on YouTube.