Hi Eljay
You not having a lot of luck are you?
Maybe you can try phoning at a less busy time, the cheaper lines may be congested. I know it says "you have run out of credit" but you never know.
How much do Onetel charge you for a call to Irish mobile ? out of interest. Arent they now part of Talk Talk? Don't Talk Talk have cheap deals to international nos where you dial a prefix . Have you asked them.
You can try webcalldirect com. But again you need to buy credit. But maybe you could use it for other calls. They give "free" calls to UK landlines and others.
Easy to use , no headphones , gear or downloads needed. Callee doesnt need computer.
JaJah com work similar to webcalldirect. In fact try them before webcall. They give a free trial call , but not sure if to a mobile. However their prices are higher than webcall.
As a last resort, from me anyway, you can try a phone card.
http://www.1st-phonecards.co.uk/http://www.thephonecardsite.com/or others ,
not italk cards.
But phonecard from my experience are not brilliant and sometimes have hidden charges. I can't see you getting a refund from any of these!
Not saying any of these will work ,but options for you.
Good luck , let us know how it goes.
Alan