Swapping iphones, but different sized SIM

[Lupa]

Need to swap phones (stood on my old one).

I'm moving from one hand me down iphone to another. The sim in the new iphone is an ee and smaller than my old iphone 4.

The sim cards are different sizes, so I can't just swap them. I've managed to move over all my content from the sim card via iTunes, but how do I transfer my O2 account over? It's just pay as you go.

In the info section of my settings on the new phone it says that the SIM is "not provisioned". I have no idea whether this will scupper anything. I attempted to do the Swap my SIM process, but it just says there is a problem with the SIM number I've enterred. Checked and double checked, but it is correct.

I'm finding the help pages completely useless. Been going around in circles for ages trying to sort this, and the guru facility non existent! As I'm pay as you go, I'm reluctant to phone CS. And there's no way to email.

Can anyone assist? What do I do to sort this out?

[MI5 · Accepted solution]

@Lupa 

You can easily get a sim with your number on it by calling into your local O2 store. 

It's free to get a new one, however, the phone sounds locked to EE so you'll need to ask them to unlock it.

[Lupa]

Thank you. Was really hoping to sort it from my keyboard!!! I suppose I'm just being lazy.

Does unlocking cost anything?

[MI5]

https://myaccount.ee.co.uk/app/device-unlock

[Lupa]

Many thanks