Try ringing 1800 200 665. That's eircom's number for requesting inclusion in the National Directory Database (NDD) to opt-out of getting cold calls.
I did this a few days ago. They said it would take 28 days for the update to the opt out list to be circulated to telemarketers.
One of the questions was can eircom still call with product info. If you are an eircom customer you have to opt out of that too to stop eircom calling.
An info sheet with this info was circulated with my last bill. It gave the impression that it only applied to
ex-directory people wanting to get cold calls(!?). But right at the end (after many people have
probably already binned it) it says that it also applies to non ex-directory people.