I've been with Verizon for 10 years now. Any issues I have are answered in an expedited fashion. If they dont have the answer at the time, they call me back with one.
One example of a mistake I made: Bill came out to 1100 over 2 months. They credited the account $800 bucks.
Verizon will work overseas depending on the phone you are using. Blackberry has cdma and gsm.