I have the same issue, I bought my A199 from Aliexpress and seller informed me that phone is unlocked.
My CDMA Provider runs on 800 mhz so itu should be compatible with the A199, when I insert my GSM and CDMA SIMs, the CDMA isnt detected
I read somewhere that some kind of ROM can beused to iinstalled on the phone? Anybody have any clue?