Seeking deferment until 21 NS to renounce.

[namename212]

Here is the current situation:

Son is born in the United States. He has stayed 0 years in Singapore, approximately 3.5 months in Singapore for vacation (over his whole life). Unfortunately, SG passport was renewed after 13, but hasn't been used before. No school system has been used in SG. NRIC has not been collected. SingPass account hasn't been set up. No other benefits have been reaped. Is there a chance the deferment is approved? I heard very slim, but for those slim it is usually those who have lived overseas their whole life and who aren't born in SG. If the parents, both renounce our SG citizenships, will that strengthen his case? How should we go about contacting the CMPB, ICA, MINDEF? Which email do we send the inquiry through? Any recommendations? Does anyone have a sample letter of inquiry doing the same thing?