You need to get the domain removed from Eircom's servers. Check the domain at
Blacknight.ie - Irish Hosting - DNS Diagnostics and you should see if eircom's servers have different information to the rest of the world.
If so, you need to send an email to
dnsrequests@eircom.net (I think that's the address) with that you want the information deleted from the servers as the domain is no longer with them.
They should get back to you in 1-2 weeks with a question and complete the operation in another 2 weeks or so! I'm waiting 3 weeks for them to complete a 2 minute job!!!