Quick update on the above issue:-
Made an appointment with Apple Genius bar, got it checked by the specialist. Ran the casual analytics diagnostic, the same one I ran over the phone with the CSO. Follow by a 10 sec viewing on the camera. Next, he told me that he will change a brand new set for me.
I was like wow, okays. That simple? lol TBH the camera wasn't that bad at all, I can't even really reproduce in the Apple store. He didn't mention what is wrong with the phone thou. Probably because of the phone still within 14 days and I have apple care+? Not sure *shrug*
He reassures me that there is no refurbish set in Apple store. You can't get a refurbished set from Apple store, you only can buy it via online and collect in store. If you bought the phone from Apple store you can get a sealed set. If it's from telco, they will open up the box and give you the phone from a sealed set. That is what he said.
Because I didn't backup my phone, so I requested to come back next time. Great service