Had this same thing happening before...often had to take the phone off the hook at night because of it. One day, after an hour and a half of this happening, I rang eircom customer service who put me through to their "nuisance calls" section... once through to there, I asked them for the number of the company that was faxing my landline (it was a blocked number!) but, they said they could not give out that information however, they said that they would contact the company and notify them of their error... Hasn't happened since!