Could it be this girl as the one you are referring to who worked
in the smoothie store? I did a few tweets search on Bedok
Mall and I checked every tweet for replies and apparently
a user by the name of Charmaine did reply to perhaps, a friend,
stating that she works at Smoothie King. And as I stalked her
profile, I noticed that she was also working on 'last saturday'
(21st December). This was the date that you claimed you saw her.
Her profile information also shows that she is a 'Mixed-Blood
Asian'. I think I have found your Juliet, Romeo.
You are welcome.
Take note of the conversation between Patricia and Charmaine.
Prove that she was working on Saturday. 
And lastly, her profile stating that she is not of one ethnic
group.
And if you managed to find her Instagram (Which I somehow did),
You will notice that she does upload pictures of her at work and if
I am not wrong, that is the uniform of the smoothie shop. I'm not
too sure about her real name because it seems like she goes by a
few 'NickNames' like "Cay" (Which obviously explains her Twitter
screen name being @killcay)
