I've recently had a couple of strange pop up messages on my phone and never had either of these messages before. The first said I'd "used my data limit and could be charged by my network provider if I kept the 4g on". Firstly my network provider always contacts me by text not a pop up message when my data is used. So I logged into my providers website and I still had over 500mb left.
The second message was when I was using Google and the pop up said something about Google being able to track my location.