ipcc File for unknown carrier - change cellular data network settings

Hello,

I bought an unlocked iPhone 5 and want to use it with another carrier. Unfortunately, this carrier is not listed at apples homepage.

For this reason I haven't got an ipcc-file from this carrier.

My problem is that this unlocked iPhone (AT&T-version) is only useable with AT&T to change the settings. That means the AT&T-ipcc-file is activated in my phone. Everytime, when I want to change something in the phone settings, I get the message, "not allowed, ask AT&T to solve this problem".

AT&T can't help me, because I'm not their custumer.

Why can't APPLE provide an ipcc-file for an unlocked iPhone 5 where you are able to use all the settings you need (such as Data, MMS,...).

For me, my iPhone 5 is still locked to AT&T although it is unlocked. This seems rediculous to me.

Does somebody has an idea how to get this option as it is shown in this link, where you can change all the settings?

Looking forward to your answers.

Otherwise I will return the iPhone 5 to Apple and go for another brand. I feel a little bit disapointed after using Apple for 15 years.

Thank you for your help.

Dee