It’s probably not that the phone is locked . Aldi uses the Telstra network on 850 MHz. Optus uses 900. It’s possible the Optus version of the phone does not have that frequency. It will never work unless you go to a compatible network. Have a look at the new Optus deals and you may not need Aldi
Hi. Have same phone. Got an unlock code and it somewhat only unlocked half of it? Can receive and send messages but not calls. Optus store won't help. Optus live chat wasn't helpful either.
This has come up a bit on the forum lately @Rachieee.
Optus supplied handsets are optimised for use on Optus owned spectrum i.e. 700, 1800, 2600 (FDD-LTE) + 2300 MHz (TDD-LTE).
If the handset doesn't support network bands used by Telstra, I'm afraid it's not going to work.
It's a handset that's exclusively sold by Optus. Therefore, it's made specially to run on the Optus Network.
The same thing applies to handsets bought overseas. They're made to run on whichever network the carrier owns/operates within the country.
We do share certain bands with other providers, but we can never guarantee that a handset will work on a carrier’s network.
You need to compare the antenna bands of the handset you purchase with the Networks available from a specific carrier. Certain handsets such as iPhones can connect to a number of bands. Cheaper handsets are less likely to offer global connectivity.
For example, Telstra may have several mobile sites that are compatible with the device, but it may not be available in your area.
There's a great site called oz towers. Plug in your address and you'll see what kind of coverage you can expect from Mobile towers in your area.