You can manually adjust the settings in More/Streaming Quality within the app menus to reduce the amount of data you are consuming.
You can also switch to a WIFI network to reduce mobile data consumption
Viewing the Sony One Service via a Mobile Network may be less reliable than via a broadband internet connection and may incur higher charges from your Mobile Network service provider.
Check your data plan with Mobile Network and internet service provider carefully to better understand the charges you might incur.