You can control how much data eStories uses when streaming on mobile networks with your Android or other mobile devices.
Navigate to the app settings and disable one or both features:
Download only over Wi-Fi. When this is enabled, you will be able to download a story to your devices only if you are connected to your Wi-Fi and your data won't be affected.
Allow Streaming Playback. Turn this off, and you will only be able to stream on the device while connected to Wi-Fi.