cosmetic won't be taxed, at least from my experience but, it can be detained if u do not have an import license and you bring in big quantity.. wat exactly did they tell u?

If she says warning this time, i think she will release. Did u have a tracking number? Perhaps you can check its status online or you send an email to pos malaysia to enquire, or you can call them. Just be careful that you dun pay money to any third party as there are ppl who tries to con ppl also, saying your goods are detained and must pay money thru some shady channels.