3 mobile appear to be one of several companies (AOL being another that brings out a cold sweat)that go out of their way to prevent you from leaving them. My wife and I have been with them for a couple of years now (we had been with them about 7 years ago but left due to poor coverage) and while the coverage has improved a LOT of calls "drop" (and occasionally there is simply no signal in areas that normally have coverage). Consequently neither of us are contactable and this is not ideal as we have 2 children. Spent about 20 minutes last night trying to cancel my wife's contract by phone (it's in my name) and with the Indian contact telling me about what great coverage it is and that I should give them a chance (we've had them for about 2 years and I still have over a year of my contract left - so I know that it's not a good service). I eventually had to hang up on the guy. I even told him that the service is a standup joke routine (Eg Alan Carr talks about having about 10, 000 mins a month for £15 and if he ever gets a signal he intends to start using them) - I think he took exception.
I tried to "chat" online today today to confirm my notice to quit and spent 20 minutes+ going round in circles.
To summarise: If you are thinking of joining 3 - don't. Don't let the low cost convince you. despite the low cost it is not good value for money. The customer service is not existent and I actually suspect designed for you to give up. DON'T TAKE THE CHANCE! DON'T JOIN THEM.