Carrier Iphone 5 carrier problem

[sancara]

Hi guys as i wrote in the title, i've got an ip5 and i'm getting odd with carrier and signal dropping. It started happening since the release of iOS 8.3. Someday (don't remember exactly) a message appear on the screen. The options where ok or cancel, choose OK. Then appears receiving data, and after that my phone never get mobile data, and the status bar fluctuate between searching and the carrier.
It's soooo annoying!!!!

I've tried, reseting data, reseting data network, changing the SIM card, restoring the ip5 w/ and without copy (as new). I don't know what to do, the problem is driving me crazy. If anyone knows the solution, please talk to me!

 

[XT550]

Reset carrier by going to settings/carrier change to manual, choose a different carrier, wait till you get no service and go back and switch to your carrier and back to auto.

 

[sancara]

Reset carrier by going to settings/carrier change to manual, choose a different carrier, wait till you get no service and go back and switch to your carrier and back to auto.

Hi XT550 i've followed your instructions, the carrier option disappeared, and a box text shows up i upload a photo. I clic settings, and the 3 carrier options appear to select, i don't change anything and i go to setting/general/about and that's the first photo uploaded.
Then i go to carrier and choose the one of mi nanoSIM card provider. Carrier disappeared, and about shows what is in photo 3. I've noticed that there's in photo 1 and 3 under about menu, the carrier is the same despite being in no service (other carrier picked up in the first case) and the one with my carrier also has it.

The problem is not resolved yet

 

[XT550]

Sorry to hear that.
Since this started after you okayed the carrier update, I presume that's what that message was, you must've already talked with them.
If the problem persists, your next step would be to take it to the Apple Store.