iPhone unlock: partly or completely?
I have an iPhone 5 running IOS 9.3.4
The phone was originally purchased through T-Mobile. After about a year I submitted a request to unlock my phone and they complied and I was able to use other sim cards overseas. No problems. I now have Consumer Cellular who provide my voice, text and data. The service that CC provides works very well in the California area where they have a presence and they are supposed to have data in all other areas with roaming included free. However, when I get to an area such as Wyoming, Montana or South Dakota, I am not able to use the data on roaming. My phone will show 4 dots of CC and LTE but I can not get my emails.
I have contacted Consumer Cellular on this and their response was, "You did not buy this iPhone from us so we can not guarantee that it will work in the roaming areas".
Now my questions:
1) Is it possible that my iPhone is not completely unlocked?
2) If I buy a new iPhone from Apple, how do I know that it will work on Consumer Cellular?
Thanks
gpKen
iPhone 5, iOS 8.2