Must have faces. Your product is clothing so your presentation should be models in clothing who represent the spirit of the lifestyle your line represents. IMHO your clothing should should be represented in full expression. Not sure who your ad agency is but you should fire them immediately. They're advice might apply if you were selling gadgets, shoes, or even watches. If so, then use a foot model, hand stand in or blue screen!
Your presentation should capture a lifestyle, emotion be it attitude, grace, rebellion, complicity - whatever. Certainly not half alive mannequins. That's my two cents. Hope it helps.