If it doesn't have to be a text message, have you considered something like ooma? I set my parents up on it after our local landline decided to jack up rates (and the ~$5/month cost doesn't hurt).i mean you have to buy the hardware, but I made the cost recovery in 3 months. For their bank, you can opt for a voice or text... So they just opt for a voice call. Pretty sure you can take the head unit overseas. The only catch might be some latency if you are far away from your calling area.