for Karachiites, i prefer buying oil from following locations for total piece of mind w.r.t originality:
METRO (all range of Havoline, Guard, ZIC - i have personally met team of ZIC there)
Bin-Hashim Mart - Shell and ZIC. they offer 10%+ discount on Shell and i buy the same from them eyes closed
Hyperstar now Carrefour - ZIC and Total
i do not trust any petrol pump of any company. its all fake business going on as most pumps are franchised - when they all do theft in fuel metering then what makes us believe that what they sell is accurate.