Did you use a free VPN when playing on FJ? If you use a free VPN then the IP might be used by other person and you are suspected to have multi accounts. Indeed FJ should give you more proofs about which accounts is connected with yours, but to be honest I dont think that FJ will scam their players just for that small amount of coins.
its make sense if dustboy said this because the VPN is use by many people and i have this experience too but in other section. the sites don't care about this and all they are know is we are make mistake so they close our account as soon as possible. i think you can trying to contact the support system again and tell that you are not using VPN and you only have one account and if they suspected that you use multi account, then you can asked the proofs. i hope you can solve this problem bro.
Reputation is very important to any gambling site and I believe the amount involved is not big enough for FortuneJack not to pay it, I'ms sure they are making great money daily and there is a reason why they last in the business for long, just comply with their requirements if they will ask you to and if they choose to forfeit your winnings and lock your account due to violation of rules, there is nothing you can do about it.