This is driving me mad, i hope someone can help, ive had the same sim card for a couple of years now had no problem at all with it, i top up on a weekly basis without any probs, but then last week i noticed on my phone it was coming up with inactive sim i thought this to be a bit strange as i had not done anything to my mobile not even switched it off, 1 min its fine the next its saying inactive sim, i tried my sim in another mobile still the same, when i called o2 they said that it could be the mobile phone but its not because ive tried other sims in it and they all work fine, so they said that they would send out a replacement sim and that any credit i had on the old broken sim they would transfer it straight to my new one, well i got the replacement sim checked my balance and yes my credit had been transferd, so i went to make a call and you guessed it, its not having none of it, i cant even text but i can check my balance which i thought strange, also i noticed that its not saying inactive sim any more, i called o2 back explained it all again they said that the replacement sim must be faulty and that they would send out another one, so this morning i got my 2nd replacement sim put it in my mobile and yes its doing the same again, so i thought maybe i should top up, even though i new it was active because my credit had again been transferd to it, so i stuck a tenner on it but nope still the same, every time i try and make a call it does nothing at all, if i try and text it says unable to send message, its the same in different mobile phones as well so i no its got to be the sim and not the mobile. So sorry if i have waffled loads!!!!