Question re: those airless pump dispensers of face cream

I won a brand new Clarins gentle night cream from ebay (brand new,
boxed, etc.) and I received it the other day. It feels heavy and full
but no matter how many times I've depressed the pump, nothing comes
out. Any tricks? It's one of those dispensers where you press down on
the whole top and the product comes out a little hole in the middle.
It's supposed to keep it fresher and less germy I suppose. I have
contacted the seller and have not heard back yet. I don't know if I
just got a defective one.... If anyone has come across this, let me
know! Thanks!
Dana