I've bought Philosophy from the Watson's store right beside H&M at Queen's Road Central. I don't think they have the complete line though. And IMHO its way overpriced here in HK than in the US - but hey, what imported product isn't? You should also consider buying online via skinstore.com. they have great promotions and shipping not too expensive so it makes it worthwhile to order from them too.
Got a "deal" coupon for 180 HKD for a 800 HKDphilosophy treatment spa handed to me last week in Sogo CSW Philosphy counter.
Philosophy's customer hotline is : 29736368
They have stores and spas in Tsim Sha Tsui, Central, Shatin, Yau Ma Tei & Sogo.