Hi Sandeep, i think i am getting the points right, ... so for me i submitted my Labor Contract which was issued from MOHRE (almost every other private company in UAE who doesnt fall under Freezone / Government / Semi Government entities ) have to get the Labor contract signed and stamp, for you the scenario is different, so i think you need to convince them that your company doesn't fall under MOHRE jurisdiction hence you are unable to provide MOHRE raised labor contract of work experience but you have to provide substantial proof to backup your case.
So, if i am in your place, i should have provide them your company Trade License you work with, It obviously says that its a Free Zone trade License and your company has established in the Free zone area, and you need to search the official links on net where it says that Free Zone doesn't falls under MOHRE Jursdicition and you can provide that weblinks to them, also you can write a clarification letter that this is the whole scenario hence you cant provide anything from MOHRE as they are not linked with Free zone system,
last but not least, I am unsure how the official contract system work in freezone, for sure you might be having the official contract which has been signed by you and accepted by Freezone authoirty and based on that you have got your visa, you need to pull out that contract in order to support your case.
Let me know if you require any help or adivse.
Thanks.