GGA Maur uses the Sunrise mobile network. Mobile plans work nationwide, not just in the Maur region.
No, all GGA Maur Mobile plans have no minimum contract term. The 50% discount applies automatically for the first 24 months.
After the 24 months, the regular price applies (e.g. CHF 29.90 instead of CHF 14.95 for Mobile Smart). Since there is no contract, you can cancel and switch at any time.
Yes, porting your number to GGA Maur is supported.