No gift for a qualifying purchase?!

I ordered 2 products online because there has been a gift promotion. When my parcel arrived there was no gift. I sent 2 emails to the customer service department to query the omission, but received no response. Finally, I decided to phone customer service only to be told that I had not selected the gift, hence they can't do anything about it. How can a reputable company decline an offer made by them? I selected the free sample, so I'm pretty confident that I selected the gift as well. I've really lost confidence in online ordering from Estée Lauder as a result of them not honouring their word.