Getting overwhelmed. single parent to a 11Yo with ADHD. Share your story

A few issue bear with me.
Centerlink sent me a overpayment letter saying. that they over Payed me around 1200$ for a backpay of family tax benefits.
when i got the letter i had been on family tax befits for 2-3 payments cause i never knew about it. my son is 11 so i missed out on a lot of help financially.
the back pay i got was around 3000$ all equally separated amongst family tax A & B and rent assistance. i don't see how i could get 1000$ back pay of rent assistance when as soon as i want on the parenting pay they reduced my rent assistance by 50$ seams strange.
so i made a review about it & they never called me to talk about it.
then they cancel the review. now I'm wanting for another review while paying the money i never got back.

they also own me 7 months of rent assistance back pay cause i never told them my rent went up 20$ like every ones rent had cause i never knew it happen, i owed so much rent.
all this combine with they fact they never call me to discuss it and i never get put in a que when i call cause, the line is buys. or to even walking in and being told by the people that work there that they cant do anything about it.
then to top it off as a single parent father, the mother never attempt to spend time with our kid or pay any chilled support. i feel as if everything is against me. because i am a male.
i just need to get this sorted out. i have only 2 things i want ATM and i cant do it.
i live in a unit, with a 11 year old that has ADHD, i need a room not a studio apartment, but when i look at rent of a house its 450$ a week!.
and i need to by a car to get my son to school safer, I'm driving around a beat up car cause some 87 year old man was driven like a brick during school hours.
but when i go on gumtree to buy a car they are all 9-10k cause some car dealerships go around buying all the decent cards for 5k and resells them for top market value. i fricken hate flippers!.
it would be nice if there are anyone else going through the same thing that they could share there stories I'm hoping reading other people centerlink drama could help me deal with what I'm going through.