Never, ever go with Three. I had a pay-as-you-go contract with them. My phone was stolen, so of course I asked them to cancel the SIM and send a replacement. They said it would be there in 3-5 days.
3 WEEKS later the SIM had still not arrived. I called again and asked what was going on. I was given some piss-poor excuse about the request not going through, or technical difficulties or some such rubbish. I then told them that I wanted to cancel my contract with them, and was told "oh that has to go through as a separate request, we can't do that until the cancellation of the other request goes through". They promised to ring me within 24 hours to confirm it, which of course didn't happen. I then rang them again and told them to give me my PAC code.
Long story short, I was passed from person to person, none of whom had a clue about any of my details or the story. You spend ages explaining everything again and again (apparently, they don't possess such advanced technology as customer records and databases) and they ask you to repeat your number each time. I told them that they should have records of my calls, and should know exactly what had happened, and that I was with my friends at the time, and telling them all never to take out a contract with Three. (This was true). I also told them I would post this experience on every social media and reviews site that I could find, hence this review.
And then, after much wasted time that I'll never get back, when I finally got my PAC - this actually made me laugh out loud - the woman had the gall to say "oh if you want to stay with us then we'll give you three months' free service"! Not if you paid me, you poor, unfortunate employee of this scummy company!
I reckon they know perfectly well that people realise they're awful, so they put the hooks in and make it as impossible as possible to cancel your contract. Absolutely disgusting. Avoid them like the plague!