CellC Not registered on network error

Saw an old thread on this, seems my issue is a bit different though.

Phone is a Samsung S4 i9500.

I noticed yesterday that I couldn't make calls, even though I still had data access. Network signal is full, and it alternates between 3G and H+. I have tried switching between WCDMA and GSM, choosing Vodacom network, switching roaming on and off, multiple reboots.

Things I have checked:

• My sim card works in other phones (points to no issue with SIM)
• A Vodacom sim card works in my phone (points to no issue with phone)
• Another Cell C sim card does *not* work in my phone (points to issue with either phone on CellC, or CellC itself)
• I have done a SIM swap (no joy)
• I have called the call center multiple times
• *#06# shows my IMEI number, it's not corrupt or null

Phone recently had a 90mb update for "stability". I don't know if the issue started directly after this (I don't think so). Does anyone have alternative solutions to try? I find it odd that I have data but no voice.

Android version 4.4.2
Kernel version 3.4.5-699287
Baseband version I9500XXUFNC1

You could download another firmware and flash that, but that will probably void your warranty.

Been experiencing the same issues

Anyone else experiencing this? Missing calls and when you try to make a call get Not registered on netwrok. However internet/3G works fine.

Got to restart phone / put in airplane mode and then works fine again.....

Have the standard Samsung rom

If another Cell C card doesn't work on the phone, problem is probably the phone. Yes, OTA live update can be blamed for. Backup your data and try hard reset (including user data), I don't have Android thingy, search how to do it. If doesn't help, download full version of 4.4.2 and flash it from PC.

Before you decide for above check if you have menu option for GSM voice network to use CS, PS services or auto/both. Select CS (carrier select) only. It is old GSM method, always works.

7years later and i am struggeling with my Note3 on Cell C. It works on the other providers, could it be the Baseband firmware ?