if you have a orange mundo mobile number and come to the UK it usually switches network for you, but if you keep it in the UK and it drops off like mine did don’t panic – change your settings so it doesn’t select network automatically, i changed it to orange and it came back on after 2 weeks of being off!! make sure you top it up every few months aswell apparently they will disable the number if
you don’t use it. I read that its best to send at least one text message a month to keep it activated. Getting through to text support is a nightmare from the UK so watch what you doing a flight to sort out your number only to find its been disconnected could be a nightmare!!