I bought an unlock code for my HTC One Koodo phone and tested a new ROAM sim (for use in the USA). Everything seems good and the sim looks like my unlock code is good. I turned off my phone, removed my ROAM sim and inserted my koodo sim back into the phone. It now doesn't seem to find the koodo network. Shouldn't it ask me for a password? The wifi works ok, but no network. Just an x over the 5 shaded bars. In the Settings, the mobile network says disconnected because the service is unavailable. Any suggestions.