About 2 weeks ago I switched my mobile phone from TPG to Optus in conjunction with connecting to the NBN via Optus.
Since then I have been missing SMS messages from selected mobile phones and have narrowed the problem down to mobiles on the Telstra network. I can receive text messages from Optus and Vodafone mobiles.
Do you have any suggestions or the best place in Optus to go to for assistance?
Tech support is where you need to go and they lodge a fault. This is a network level issue on Telstra's end I believe but Optus is your supplier now so they need to work on your behalf with Telstra to resolve it. You'll probably find you can't receive calls from Telstra handsets as well, right?