A number appeared on my iphone that it's not the number I've ever had and it's affilited to facetime and iMessage

It says it needs to be shutdown on that iPhone but as I mentioned, I've never had this number so I don't know who apple device is this. And because of that I have no access to that phone to remove the number. Is there any way that number can get deleted or removed. The fact that someone could get my information with that number really scares me. in my country my only options for support are contacting the mobile carriers but they know nothing about it.