EU roaming calls/texts add-ons are for when you are roaming abroad in the EU and want to make calls/send texts.
They are not for calling/texting EU numbers when you are in Ireland.
The purpose of the add-ins is explained here:
Sounds like you should not have bought the add-on and it will do no good here.
To call/text international numbers you need cash credit on your account and the calls are charged from that cash credit balance.
Details of charges are here (50c per minute and 25c per SMS to UK).
Hope this helps