As we are fellow users, you're not talking to iTunes Support here, I've asked the hosts to remove your email address from your post.
Where did you buy it ? If it was in the UAE or Saudi Arabia (and possibly a few other countries) then you won't have it due to restrictions by those countries governments, and it can't be installed (inclduing by iOS updates).
Where was the iPad purchased?
By Government Regulation iPads, iPhones, and iPods soild in the UAE and some other middel eastern countries are prohibited from having Facetime.
To comply with said regulations Apple removed the Application from the devices.
There is no way to install it onto these devices either.
You can check here if the country of purchase for the iPad is amongst those that do not allow Facetime.
Facetime can also be made 'invisible', if it's locked out in restrictions then the icon disappears. So if your device isn't from a country that prohibits facetime, you could look into your settings and the restrictions. Also, if your iPad is school or company provided, they could also have locked it out.