The terms you have to meet are the initial terms you signed up to prior to use. As far as I know your given a 1 month trial period where you can switch it off without any charges, whether that means your liable for the full first month I don't know i wouldn't think so but it has to be written somewhere whether you are or not.

Eir are renowned for pulling this shit, just start recording all the calls you make to them in case it gets messy in the future, there's definitely some kind of ombudsman service available that you can get in contact with, get all your info in place and if you 100% right go after them, they will settle with you under any viable threat.