Unlocking iPhone 5 with EE UK?

On their site, it says that it costs £20.42 to get an unlock code. I just have a few questions. Is the total price £20.42, or is that just a preorder cost; and you have to pay the rest of the cost after (like some other unlock services make you do)? Also, can you only pay using credit/the cost being added to your phone bill, or is there another way?

Is the unlock code permanent? Do they jailbreak your phone (although it is very unlikely, I just want to make sure)? How do they actually unlock your phone?

Thanks in advance. Your answers are much appreciated.

Unlock and jailbreak or two different things. Unlock means a carrier code is forwarded to Apple and their servers to show the phone as not paired to any one carrier so the world potential of the phone is available. Jailbreaking is altering the iOS to make it do things more like Android or things it doesn't normally do. Being a carrier service you can probably pay for it any way you want. I don't think they'll refuse to take your money. Yes, Unlocks are permanent. Not sure of EE but that should be the total price. I would pay more than that. That's $34.50 USD and seems steep enough. Best luck.