Apple ID stolen by a random MacBook

So I have someone that has stolen my @Gmail.com, my original Apple ID, and is right now actively in my current new Apple ID. My question is is how I get them out. The best way to describe the way they have control is that they can actually see what I’m doing on my phone. They can changes settings and open apps at will. It’s not spyware or ransom ware because they actually pull up searches on my safari and look up how to as they go and disable my ability to stop them. I went to Apple they said it’s impossible that that’s happening. So can it happen and how do I stop it forever is my question please help me I’m about to lose my business if I can’t