Just to give some update. Yesterday I received a replied from SQ on my "complain" which I file almost 2 months ago.
Seriously I did not expect anything other than the standard thank you email and we will feedback into the relevant department.
But the email was quite a surprise. On the contrary, SQ looks into this as as serious matter not a small matter as many here put it.
Here is the email quote
We apologise for the disappointment caused with regard to the cabin crew service on flight SQ949 / 14 December 2016. We expect our crew to serve passengers with professionalism and attentiveness at all times and understand that it is further disappointing that their handling of the situation did not meet your expectations, Mr lingua101. We sincerely regret your experience on this occasion and wish to assure you that this is not our usual standard of service. We do take such feedback very seriously and as such, your experience has been highlighted to our Cabin Crew Performance Manager, who will follow-up internally with the crew concerned about their service skills.