My calls are automatically routed through another provider, but I pay line rental to Eircom. Can I still use call13434?

To have all your calls automatically routed through another provider is also known as Carrier Pre-Select (CPS). You will still be able to use call13434 as usual and this will not affect your CPS subscription. Just sign up and dial 13434 followed by the telephone number to make cheaper calls! Your CPS provider will not charge you for dialling the call13434 code, therefore the call13434 code will not appear on your CPS bill and any calls made using the call13434 code will only be invoiced by Call13434.