What the heck don't these people understand about NO. Called the number back today and recording says, "you have reached the advanced intelligence network. You are not allowed to access this number, please hang up. How do they define "intelligence" when they don't know what "NO" means?
Returning these calls to unknown numbers isn't necessarily the most intelligent thing to do on your behalf, though. Say you actually get someone, what are you going to do, tell them to stop calling? That's something a lot of these idiots don't understand, calls that always have ANY kind of answer are the ones they'll be calling. Many of these numbers are dummies to help pests remain anonymous. You want them stopped, try not answering mystery callers in any way if you're able. They'll eventually get the idea you're not playing and stop bothering you as much.
Bell has the technology to screen these callers yet sits back and chooses to do nothing. Bell is about as useful as the CRTC. Paid tv advertising for my latest invention: "programmable telephone call blocker" - just push a button and the caller's number is saved while the caller receives a high-pitched squeal that will deafen and cause them to think twice next time. Automatically blocks the number from any repeat calling. Just $29.95!