I am kinda worried may be there's lot of rust inside it and one day it's gonna snap and electrocute somone. Whom should I call to fix it? Sparky ? Welder ?
Also, Its a duplex so should I ask my neighbors to also pay half of whatever I get charged to fix it ?
Some more pics -
Start with your neighbour, there's two power lines running off that thing so have a friendly word about preventative maintenance.
Then I'd call your power company about the issue and ask them the process. Your power company will contact the wholesaler for a tech or refer you to the wholesaler for a tech visit.
You'll also want a sparky to wire the fuse boxes to the new raiser. And maybe even a builder to do a premium job of attaching the new raiser.
You'll have to get a new elec-mounting thing installed and wired up to both the mains and house power. Ideally you'd get both parties to come on the same day to sort it with little downtime.
Does it wobble in the wind or with birds on the line? Maybe it's just been bent at some point but is still strong. I wouldn't go poking it to check unless I had a big piece of plastic conduit, wood or metal might conduct electricity.
Were I to get one of these done, I'd get as tall a raiser as allowed on the off chance I need to put a truck or caravan underneath.
Some hardware examples: https://tle.mmem.com.au/power-cables-accessories/consumer-mains-hardware/raiser-pole-brackets?p=1
R/auselectricains might give you a better answer.