[randomguy]

I had the same issue years back with Virgin phone numbers I moved to BT got a new number and never got a single call. I think Virgin reuse their phone numbers too quickly. I think in some instances a month after its disconnected.

There should be some database that all companies use that when someone disconnects a number they are notified and any contacts with that number against their name can be removed.

You could always register with TPS that's another option.