Yes it depends. My sister had no landline for some months and both mum and I complained when we found we had $100 phone bills calling her cell phone a few times. Often we got calls from her when she was at work at the end of the day as she had run out of credit on her phone so couldn't call us. She also didn't have the internet so was either at my parents place using theirs or at work.

Both of us told her- enough is enough, get yourself sorted, otherwise no free internet and we will stop calling you.