I have an unlocked iPhone 5 purchased from Europe and would like to use it on AT

Question

Hello-
I purchased an iPhone 5 in Denmark where I live.  It works fine here and when roaming.  I travel to the US every month and therefore have a post-paid full AT&T account.   In fact it is a shared data plan and I spend about $700 per month just from AT&T.  I have had an AT&T account for years but recently moved to Europe.
I can put my AT&T sim in my iPhone 5 without issue, and the basic GSM features work.  In fact, the phone recognizes 4G.  That said, the phone does not support mobile hotspot, FaceTime over cellular, no LTE,  or visual voicemail.
I first went to the AT&T store, and they said no problem.  They swapped my AT&T SIM card, and added features to my account.  However, after several hours still no joy with the advanced features.
  When I called AT&T, and explained my issue, they escalated the call to tier 2 tech support.  They escalated it again and said it is an IMEI problem.  Basically, AT&T does not recognize the IMEI of my phone,   They view my iPhone 5 as a generic GSM phone.  I asked them to just "force it" and put it in their database, but they said AT&T was not allowed to do this.  Evidently, Apple does not allow AT&T to classify IMEI numbers.  Their system needs to know that the device is an iPhone 5, and that the only way they can do that is via the IMEI.
So question, how do I get AT&T to recognize my iPhone 5?  I don't want to carry two phones, and just want to be able to swap my SIM card when I travel.
I know that LTE will not work because AT&T uses 700 MHz for their LTE and my phone supports international LTE specs.
Thoughts?

Answer 1

It sounds as if AT&T has already told you they can't do what you want. It doensn't sould like anything that's fixable on your end.