Ive just received my Giffgaff sime. Ive activated it online, but when I put it into my phone (Samsung Galaxy S11) it asks for the Network lock control key. Where do I get this from? Im currently with three network.
Yes, you need to get you S2 unlocked either by visiting a phone shop, or do it yourself by following this set of guides:
You can check that the S2 is in fact locked by daling this code: *#7465625# (View Phone Lock Status)