O2

Seems my first message went astray! Just joined O2 I was given stac instead pac number (not know difference until replied not taking old number) I now have pac number, and I am waiting the sim. Trying to change to old number just sends me on a loop- ...

I have just order a new 02 sim and gave a stac rather than PAC number. Sim due within 24 hours can I change and give a pac number before sim arrives? My new account has nothing registered in it (it says to sign in and keep your old number but no link...