TAMPA, Fla. — Floridian Rene Remund and his wife toured Switzerland last September. But when they got home, their cell phone bill had jumped higher than the Swiss Alps. Remund and his wife said they travel frequently and always notify their cell phone carrier before they leave the United States. In this case, Rene said he visited a T-Mobile store to share his travel plan. He's also been a T-Mobile customer for nearly 30 years. “They said you’re covered. Whatever that meant. You're covered,” Rene said. The couple took a trip that they described as magical. As they toured the...