I have bought 'stuff' online before, I bought some Zopiclone when my GP stopped it, I had been taking it for over 10 years previous to this, and I can tell you for sure the 'stuff' that I got was NOT Zopiclone!
I also bought some Diazepam once - but it was very very strong... It's not something I would ever do again, (also cost me a fortune, money that I did not really have) like others have said it's very dangerous... I just wanted you to know it's really not worth it.
I actually am prescribed regular Diazepam now and I recently recieved a copy of a letter that my Psych sent to my GP to say I will probably never be able to come off it, as I have took it for most of my adult life.