Frustrated to get PR in Singapore

Becoming PR is a privilege, not a right.
To understand who is accepted and why, you need to think not in what the PR status would give the applicant, but what the applicant can give Singapore.
Having only an S-Pass (thus low salary) and no kid, they see you as a drain on Singapore's limited resources and space, rather than an economic enrichment.
Wait until you have a baby (boy preferred because of military service) and a higher salary (at least S$4000/month, which you anyway need to be allowed to have a dependant - i.e. the baby - in Singapore). Then apply all together as family!

Thanks for your advise beppi. Appreciate that.

But as mentioned too, i have friends who are single, lower job position who passed the PR...

No two cases are the same, or even comparable.
Maybe your friends who became PR had other things that Singapore finds desirable, e.g. education,skills or job scope that are rare and needed here - or they were of Chinese ancestry (a BIG plus!).

Instead of baby, unless both your hubby n you wanted it for family reason,, perhaps you can consider :

(1) participate in community work, to integrate with the locals
(2) be a member of an association or body in Singapore which serves the peoples of Singapore
(3) be a regular donor to approved charities in Singapore
(4) invest in immovable assets in Singapore, on long term basis
(5) do anything that impact positively to the local community
(6) upgrade with a qualification from institution in
singapore, on going is better
(7) maintain a good standing track record as residents here.

if you have a network of local friends who can help lobby for you, maybe it would help too, this aspect is just my thoughts. I have helped my clients to get PR and EP before, basically you just need to prepare your substances based on facts and not apply with nothing to offer.

I suggest to look at overall profile and what you and your hubby can do, write a comprehensive report, meet officer to hand over, attach all references etc etc. Showcase why both of you want to be in Singapore as permanent residents, any personal attachment etc.