I just got an iPhone 4 and I'm trying to use it on tmobile. I have restored the phone but every time I put in my SIM card for t mobile it says no service. How can I fix this?

How do you know the phone is unlocked?

Have you checked with T-Mobile?

From where was the phone purchased?

That site is a bunch of hooey. Only APPLE maintains the database of it's unlocked phones. I'll ask again: where did you purchase your phone?

I agree with GDG, that site is not trustworthy.

Usually when you are told your phone is unlocked but it does not work with another carrier then it was hacked to unlock. If you bought it recently return it to the seller, and/or report them to eBay for scamming people.

Purchase an iPhone from a legitimate source: T-Mobile, or purchase an unlocked phone straight from Apple.

Just as I figured. Your phone is almost certainly NOT unlocked. You can call Apple with the phone's serial number and find out to which carrier the phone is locked. Probably AT&T. If you're not an account holder with AT&T, it's very unlikely they'll unlock the phone for you.

You need to purchase an unlocked phone from a legitimate source, and in the US that is Apple.

If a phone is sold from one friend to another and wants to use it on a different carrier the friend can contact the carrier it was sold by to request it unlocked. I know AT&T, Verizon, and Sprint will give you the steps to unlock it as long as the original contract it was bought under has been completed. eBay/Craigslist is really not the best place to try to get "unlocked phones" from, if it turns out the phone isn't unlocked then I'm really sorry you got stuck with that one and as stevejobsfan said above I would report them immediately and see if you can recover your money. I sell phones for a living and this happens a lot 😟

When you put the SIM card in and activated it with iTunes you did not receive any error messages and it activated on T-Mobile?