Waiting for Vetting Agencies Result - Singapore EP

Hi,

I am from India and I have been offered a job in Singapore and my employer has lodged my EP application online about 15 days ago.

My visa application is still pending and waiting for vetting agencies result (as the current status is), while most of my friends from other colleges in India have got it approved within 5-7 days only (whose EP was also applied by the same employer, on the same date and they have also been offered the same job at same compensation as that of mine). Mostly all of us are fresh graduates from Top Engineering Colleges in India.

What is the purpose of these agencies? Is it verifying the degree or something else.
I sent scanned copies of my original documents while submitting and all the information provided by me is truly genuine. Also my credentials qualified the "Self-Assessment Tool" on MoM Website for both S pass and E pass.

When can I expect the result and can it get rejected? My employer says max time is 2 months in this case. And also is this check by vetting agencies performed on all the applications or on some only (If some why would have mine be selected and not others also)

Waiting for reply.
Thanks