So, here's how things work, usually.
Your router connects to the modem (or maybe it's an all-in-one), the router gets a public or external IP from your provider through the modem. Each device you connect to your router gets an internal IP for communicating within your network. As far as things outside your network are concerned EVERY device accessing the internet from "inside" your network is connecting from the same IP. In this configuration someone can't directly use the address you can see in the phone status in order to control the device from outside your home network.
How can you change this external IP? Well, if you unplug your router and modem for around 30 seconds it's possible the router will be assigned a new external address, but the way those assignments are registered (through a "lease" that expires after a period of time set by the provider) it's possible you could pull the same external IP.
What evidence do you have that this control is actually happening?