Some events have very large data sets that are received whenever the app has access to the Internet. To only use the app with Wi-Fi and not impact your cellular data plan quota, simply apply the following settings:
iOS
Settings App > Cellular > scroll to find the app > set the toggle for using cellular data to OFF
To further avoid using cellular data, ensure to turn off WiFi Assist
Android
Settings App > Mobile Data > Open the app under Data Usage Stats > set the Background Data toggle to OFF
Steps to access these settings may vary depending on your OS version.