How do I contact them

Hey so I have been missing coins now from two of the games that I play. Now I keep playing the games as I like them but I have filled out so many of the "missing coins" forms and still haven't herd anything back from them. I've checked my emails spam folder as well and still nothing. It has been 3 months since I reached the certain level you need to and still haven't received coins. It seems to be the bigger payouts they won't give you I would like to actually talk with the people who run this app and find out why they haven't even bothered to respond or why put large wining amounts of coins for reaching certain level of the game if your NOT going to pay. 

And on another note why is my friends vouchers only 5000 coins and yet mine is 6250 coins for the same vouchers surely they should be the same 

Can anyone help me