There aren't any solid rules about commcodes in Core, or even in either of the expanded Matrix books that I've read, so I feel like this is another thing that GMs should hand-wave or house-rule.
So, the IT analyst from the office building you infiltrated managed to get your commcode, and can tell whether you're online or not with a Matrix Perception test looking for the persona/device with that commcode.
So, what then? You need marks to trace the physical location of that icon. With just the commcode, you can really only send messages. Plus, once you've escaped, corporate's probably going to want to focus on damage control, since there's no profit in pursuit. Right now, I can think of two potential ways to handle this:
Black Trenchcoat: "I forward any calls through my burner commlink, which I'll replace as necessary after every couple of runs."
Pink Mohawk: "You get another call from Aztechnology, asking when you're planning on turning yourself in."
"That's it, I'm blocking & un-friending them!"