I've added the Caribbean ($40) plan which I'm hoping I'll be able to use while in Holguin Cuba next week. Do I need to keep data on during the time I'm away, or should I turn it off? I'm a bit confused. The feature I want to use most is the text messages. When I make a call to Canada (I have 50 minutes), am I charged for extra roaming? What if someone phones me from Canada?