First of all Jacky in Star One Mobile gave me the best price, ( he omitted to say the price given was without taxes) the difference was about 90 SD, then he presented an IPhone out of the box that I refused, Jacky then left for about 15 min and came back with what he said was a factory sealed IPhone package.
He assured me that I would get a tax refund on my departure the same day to Batam.
After the reaching Harbour front I found out that the only tax refund I could get was from the airport itself.
After arriving in Indonesia, and trying to activate my phone, the phone was a total brick, unable to come on.
I planned to ask for a full refund on my next trip, I will go as far as filling a report to the Singaporean Police if I don't get satisfaction.
Below picture of Jacky the salesman / front of the Store ans attached receipt