EP rejected due to not serving NS - Born Singapore PR

Hello everyone, I'd be grateful if someone who have heard of this or went through the same experience  to share a bit with me

A little background about myself:

I was born a Singapore PR, but moved to Malaysia since 12. I surrendered my PR when I turn 18 as I decided to pursue my Degree in Malaysia and not serving the Singapore NS. After my Degree, I have been working in Malaysia for 5years (in reputable audit firm), and I'm now seeking for an audit position in Singapore.

My EP application was submitted 16/6/2021 and was informed that my application was not successful after processing for one month  due to the following reason:

Under the Enlistment Act, all male Singapore citizens and Permanent Residents (PR) above the age of 18 years are required to serve National Service (NS). We note that your candidate did not fulfil his NS obligations. Those who give up or lose their citizenship/PR status without serving NS will face adverse consequences when they attempt to work, study or live in Singapore.

Does anyone heard anything about this? Any chances to appeal? My employer says is unlikely to be appealed and they couldn't process my employment further.

Thanks for your comments.