My wife's new Galaxy 5S has LTE/WCDMA/GSM as the network mode. The network operator shows YES OPTUS but she cannot make or receive phone calls, Does she need a different SIM or a is there something we are missing?
Nope, that phone should work - particuarly if it says "YES OPTUS". Does it allow you to use data, and/or send SMS messages?
Have you spoken with our 24/7 Tech team to look further into this to see what might be causing this issue?
Does the SIM card work on any other device with no issues?
Thanks @Comb, that's certainly unusual.
Was the phone purchased from Optus directly?
Is it still covered by warranty?
If so you will need to take it into your local Optus Store as we may need to send it away for repair or replacement.