You have also an alternative option, apply via online.
I've experimented on Singtel CIS online application, it's requirements are your email from your company (to validate the company fulfill CIS company size requirement).
After that select your desired new phone and subscription and finally, attached your last month payslip or IR8A and photocopy of your NRIC (both sides) for confirmation.
Select home delivery or post box for collection.
That's it. This is the steps that I remembered, there maybe some steps that maybe wrong. Hope this is useful.
Need what documents aside from IC and staff pass?