After four months plus, here what the Traffic Police wrote:
We have reviewed your case and note that a traffic offence has been disclosed but in view of the circumstances, we have decided to take no further action against you in this instance. However, a warning will be recorded for our future reference.
Double checking the status at Singapore Police Force website, I have no outstanding summons. Yeah I saved $70! If not I will lose $70 because of the $30 Robinson vouchers.
Note: You can appeal through email to Traffic Police Feedback Unit at email address SPF_Feedback_TP@spf.gov.sg. URA and HDB appeal through their websites at http://www.ura.gov.sg and http://www.hdb.gov.sg respectively.