MapPress uses Algolia if you’re using the Leaflet engine, and Google geocoding if you’re using Google.
So, the easy asnwer is to switch to Google and use their geocoding.
Both services provide a way for you to report errors, and I think they’re botth pretty good about correcting them.
With that said, I’m confused about where the problem lies. When I type ‘Kallangur’ (by itself) into both Google Maps and Leaflet, they come up with a marker in almost exactly the same place (near the intersection of Anzac Ave and Old Gympie Road).
I also got the same location on openstreetmaps (on which Algolia is based), and geonames returns (-27.25204, 152.99226) which is the same.