ram problem?

[HPTL7]

I bought a 8gb ram stick of someone from ebay.
I put it in my computer, new setup of windows, once fully installed, checked cpu z. Only 4gb ram. No manufacturer name either. The actual ram was from ********. The ram stick has a sticker on it saying 8gb

I installed 64bit so it should detect more than 4gb. Is there something else im missing or have i been 'sent the wrong item'

Thanks

 

[HPTL7]

defo only 4gb. tried in a new pc.
and yeah i only received one.

 

[HPTL7]

okay thanks. I have contacted him.