How to unlock IPhone 5 on at&t?

I'm trying to switch over to t-mobile and I wish to keep my phone. I went to at&t and asked if they can unlock it, the guy was a completely useless and he was also an ***! So is there any other way to unlock it?

IPhone contacts don't display?

It appears my iPhone has deleted about half of my contacts, in my messages app there's a bunch of numbers where there should be names, and they are not in contacts app, also I can't make them new contacts. However if I go to the button to make a new text message and in the "to" bar when I search the name my contact pops up but still displays a their phone number instead of the name. I tried calling apple an they said it would be 20$ for their help so that's not happening.

What imac is this and is it worth it?

Http://www.gumtree.com/p/for-sale/apple-imacs-for-sale-core-2-duo-will-deliver-intel-imacs-perfect-with-ipad-and-iphone-or-mac/1027267032#photo-content
I'm looking at the 17 inch one btw

Added (1). I have a decent pc and just wanted a cheap imac to play around with thank for your help i have £210 so if you could suggest a model that is around this price i will be very thankful: D

How long will the iPhone hype last?

Like the blackberry hype went on for a few years and now it's looked down upon to have a blackberry infact if you don't have an iphone at all! Will iphones ever go out of fashion?

Can you still use an Iphone 3G even if it's old?

I just bought an Iphone 3G at a discounted price and it's unlocked. First of all, can I use it to text and talk?

Second, I have a verizon pre-paid account, can I port my number to it and use it as a pre-paid phone?

Third, it has minor repair issues such as having to talk extra loud because the microphone has issues and it shows the battery isn't charging, but I was told it works fine, how much am I looking at cost-wise for repairs?