Dude, repayment of RM 500 - RM 1,000 is laughable.
Even standard loan from 15 years ago is minimum RM 300/month repayment.

Own up your debts. It's not going anywhere. Whether this agency is bogus or not, the fact is you're behind repayment schedule.
Go to PTPTN kiosk and tell them you want to restructure. It's not hard.

No probs. The first victory is always the acknowledgement and owning up the mess created.

I'm also one of the bugger last time.
But PTPTN officer are very helpful. They will ask what amount you can pay, then you just direct debit.
Then just follow strictly.

Sometime will have promotion, like timely repayment will get 10 or 20% discount.