Solved! Solved: Go to Solution.
Have you tried going into the phone app > pressing the 3 dots in the top right hand corner > selecting settings > block numbers and then selecting "recents" to show recent calls you've received and selecting suncorp that way? That's the only option I can think of.
As for the calls from the Optus number, people are able to "spoof" phone numbers these days which makes it look like a call is coming from a phone number when it's really not. You've done the right thing requesting it be investigated, the rest is up to Optus/Law Enforcement.