If you bought it from a reputable source and paid a fair market price you can be reasonably sure you received what you paid for.
However the rule of, "If something looks too good to be true...it probably is..." should be a watch word when buying on the Internet.
If it has the name but not the price, chances are it will be a Knock Off, and You will have been screwed !!
Oh Yes ! Just so are in no doubt in most genuine countries it is as illegal to buy forged products as it is to sell them.....