I've started to get little icons at the top of the home screen (I mean that place where you get the battery icon, time, etc). These icons may be a star or smiley, etc, and when I pull down the 'roller blind' there's a little message, such as 'Try a 3-2-1'. Tap on the message and it fires up my browser. These aren't emails, so I assume they're linked to my phone number -- ie, some sort of text. How can I stop them, please? Thanks in advance.