O2

Hi o2 communityI upgraded to the iPhone Pro max a few weeks ago online and o2 asked me if I wanted a new SIM card which I pressed noSince then I've read the iPhone Pro max needs the new SIM card to work much faster,is this true and if so how do I now...

hi anyone know how I can get my passcode to login to my previous iPhone with o2 and I'm still a current client with o2 and the previous iPhone was also purchased from o2