User Activity

We have a nil spend cap and a relative has recently moved from the UK to live in Spain. He now has a new international phone number. We have tried ringing it and it is barred. How do we get access to his number and how does this work with our billing...
We are thinking of ceasing with our broadband supplier and wonder if a dongle would be a suitable replacement as we do not require a landline. What do we need to have to use a dongle for our online use?