My verizon iPhone 5s is still working?

What I mean by it is, ok so I already switched my service to a lg G3. But the data is still working on the iPhone, the data works on my lg G3 too, but the iPhone seems to still have service? Help or is it a glitch? If I use it will verizon know?

I would look at this as a good thing. It might be though that your iPhone is running off of the Wi-Fi. If it's not, so what? This seems like more of a good thing than bad thing