Yes, aslong as the phone is unlocked to any network.
Yes - you need to either get Orange to unlock it - or take it to a phone shop for them to do it (either way you'll pay a fee). Then get your Port Authorisation Code (PAC) from Orange and give it to O2. The PAC locks you to a specific network, and O2 will need it to lock your phone to their network.
you can find it in orange O2 and I think Nokia but I `l go for Nokia
Yes, you can as long as the O2 phone is unlocked, then you can use a Vodafone SIM on it, or a SIM card from a different carrier.
When you have a phone unlocked it simply means that it will accept any sim card (any compatible sim card). So once its unlocked you dont have to worry about re-locking it. You can put your 3 sim card back in if you want, or an orange one or voda or keep the o2 one in. Its your choice.
if the phone is unlocked
you can only get Genie from O2
There are a couple different ways one can get a free Vodafone SIM card. The best way to obtain a free SIM card is directly through the Vodafone website. You can get a free SIM card when you sign up for Pay as you Go service.
One can get O2 international coverage by contacting them and making sure that the sim in the phone is suitable. If another sim needs to be bought then make sure that it is an international one.
Mobile phone service O2 offers free texts, some unlimited, in many of its Pay and Go and Pay Monthly tariffs. Free texts are available with both the Sim only and Phone and Sim deals.
You can get a "Simplicity Sim" from o2, which says there is no contract, but you can keep your number and phone. It is kind of like a pay monthly deal, except you can choose any phone to put the sim card and you can choose to pay for 1 month or 12 months at a time.
Nope. theres no way atall.
Go to O2 customer services or an O2 retail store to sort out the problem. Make sure that it is actually an O2 SIM card, if you can't be bothered to go to O2 just get jailbreak software I don't recommend it though, if I were you I'd get off your backside and get to someone who's with O2...