@dohnuns this may happen if you have a Data Limit set up on your phone.
You can remove this by going to Settings > Connections > Data Usage > Adjust settings accordingly from here so you can stop or amend these notifications.
@Majestic Glad to hear you found something that works.
Alternatively, you can turn off the Data usage warning from the above steps, then when in the Data Usage screen > Mobile Data Usage > The clog in the top right > Disable set data warning.
Having this notification on in no way intrudes on your personal data in any way, it is simply a notification that can be sued to manage the mobile data usage on your phone.