Who do I call to check on this?

Hi All,

Looking for advice here. The concrete platform in front of my house, has separated from the base, leaving a noticeable gap. This is the first time it’s happened in 9 years, and recently, several internal doors aren't closing properly (some won’t close at all and stays ajar and stuck in the door jamb).

I did have underpinners in around 2019 or so, and they removed stacks between the stumps and the base of the house, which seemed to help for about 4 years where the doors closed well and there werent any cracks forming along the walls. But in the last 6 months, things have kind of gone back to how it was or actually even worse than before.

The house was probably built in the late 70s/early 80s, sits on stumps and is on a corner block with a 10-15° slope and it's in the Knoxfield area, Victoria.

The concrete in the front separating is what's got me concerned the most as I'd never seen it happen before. Should I be worried about the gap, and who should I contact to inspect it?

Thanks in advance.