Yes, my advice is not to do anything relating to debt by telephone.
Get it in writing from Bord Gais, from EIC and from everyone else. Either on paper or on email.
Refuse to discuss it on the phone, don't answer their security questions, tell them to write to or email you, keep a hold of your responses as well as their communications.
Get a copy of the taped conversation yourself and have a listen to make sure you have not misunderstood.
Advise EIC that you will pursue them for harrassment if they do not prove that the debt exists, that you are liable and that they are authorised to collect it.