You do not need to prove it, pending for 6 hours is still OK as long as they notify you through your registered email. Usually FJ's players will be notified if the withdrawal is in delay because of a reason such as security check or something else.
Have you checked your email? As sometime players needs to confirm the withradawal for some cases like once players change withdrawal address or withdrawal for the first time.
I got the email where says security check. I just say its weird they dont give a time, how long will take, or something concrete. That was my problem. Never said they scam or something like this.
Best thing to do is to wait since maybe the management is doing some sort of investigation on your withdrawals and you don't need to worry if you don't do any abusive acts by playing so relax and wait for the verdict.
and if 24 hours pass and still no response then its best to follow up their support to get a response.