Hi there. idk where else to really ask this, I have such little knowledge of legal and bureaucratic stuff. I'll try to be as succinct about the situation as I can but
tl;dr: my mum is being treated in a way that is very clearly meant to make her out to be non-compliant with inspections when that is not the case, so she can be evicted for the land to be resold. Who do I go to to raise a complaint?

My mum lives in Bellambi, NSW. Right on the coast. Like literally the beach is out her front door, it's a gorgeous area. She as an 18y/o new mother fleeing a DV situation in the late '90s was fortunate enough to land in a 2-storey townhouse in a quiet cul-de-sac with baby me and her twin sister (who currently lives in Vic, not really relevant other than she just isn't in the household anymore)

In recent years it's very publically known that that area is slated for redevelopment into higher-tier housing. There have even been local rallies and protests about this, and she's smack in the zone that'd be considered prime realestate

So. The past I dunno, several months? She's been having inspections scheduled by department of housing, or whoever it is that oversees this stuff.
It's important to note that my mum is always home, almost every single day. She is very ill, immunocompromised, suffering from chronic pain and lifelong anxiety and agoraphobia. She's very rarely out. She does call ahead within a reasonable time if she happens to have an appointment on the requested date.

The past several times now, she has been home, doors and windows open, doing her best to make it clear she is home and awake. And no one shows up. She calls their office, and gets the same kinds of wishy-washy answers and reschedules, only for it to happen again. (I'll have to ask her to give me some examples of things said, I'll come back to edit)
My mum's a very shy and non-confrontational person so I know that she'd be being polite and apologetic even though this isn't her fault. She'll either be home and no one shows up, or actually not home for once and despite giving notice well ahead of time, get a text saying they showed up to no answer.

This latest time, after the same thing happening with sitting home all day and not a peep from either side of the house, she got a text message saying next time they will bring a locksmith.
...What?? She's been home every time! She's tried to tell them this.

It reeks of malicious misconduct. They're trying to paint my mum as a problem tenant so they can have reason to boot her.
I don't know how else to interpret this behaviour other than literally fucking bullying a traumatised, disabled woman who in every way is the least problematic tenant on that entire street. Literally all she does is read and garden and play WoW and keep to herself, no drinking, no drugs, no parties, never misses rent.

I just have no clue who to talk to about this. What kind of local officials do we have to go to? Who wouldn't also be standing to gain from the area my mum is in being redeveloped? Who would actually do anything, like investigate the department doing this?
I'm certain my mum isn't the only person being treated like this, especially as a lot of the folks in that area are like my mum less-affluent without the money or means to hold out in any kind of court stuff. In my mum's case especially the stress would make her poor health even worse. What can we do? When it's such an obvious case and it's basically the government we're up against...is there even anything we can do!?