My 78-year old mother traveled to Denmark to visit the exchange student she had as a teenager. She had me download Whatsapp so we could talk, but she keeps texting me and I keep replying to her on whatsapp because I have no idea how much using texting will end up costing her. I'm not sure she knows what she's doing, but I suggested she might need to be on wifi to get it to work and she claims she is on her friend's wifi. I don't have the will to try and diagnose her network issues from across an ocean via text message.