There is no such thing as an "international" version. Or international specifications. All iPhones are region based.
Unlocked iPhones can work in all regions regardless of what region they are meant for specifically. But will still have the specifications for the region they are meant for, and any restrictions applied there will be in place.
If you ordered one with dual physical sim cards for example, then by definition you would have gotten a Chinese model as that is the only place such models are available.
iPhone's for other regions outside of China, Macao and Hong Kong do not have dual sim slots.
What exactly did you order? From where did you order it? What were you expecting to get?
You can verify the model number in Settings->General->About->Model, or on the box itself, to identify the country the iPhone was meant for.
Model number M####XX/A
If the XX part of it shows
LL = North America
CH = China
AE = Arab Emirates
etc...
You can see a full list here: https://www.theiphonewiki.com/wiki/Model_Regions