Telkom prepaid sim with unused unexpired LTE bundle stops with OOB message

[ajax]

I bought a new prepaid sim in December to test Telkom LTE. I loaded a 60 GByte LTE bundle (valid 61 days). Worked great. I used it in my ZTE mifi every other day or so.
I have some 50 GByte left until 20 Feb. I popped it into my Huawei B618-65d yesterday (31st Jan). I got a OOB message saying I need to buy more data. After changing bands a couple of times it started working again. This morning, again no internet and a OOB message. Cycled bands a few times and it works again.
My LTE topup sim (180+180) works great in the Huawei and ZTE. That's in the same location where the Telkom LTE coverage is great. I have no idea why the prepaid sim is doing this. I would like to finish the data though. I guess I could transfer most of it to the topup sim.

 

[Jason-ZA]

It might be that your Huawei is connecting to the TelkomSA-R network, and the LTE bundles only work on telkom towers afaik.

Try disabling TelkomSA-R roaming and reboot, it's one of the options when you dial *180#

 

[ajax]

Aha so what you're saying the prepaid sim has roaming enabled and the topup sim has it disabled. Thanks. I will check.

 

[ajax]

The prepaid sim was indeed enabled for Telkom SA-R.
Had to switch the router from 4G only to 3G/4G Auto to get USSD to work. Shortcut to the setting is *180*13#