UB froze my acct and funds - tell me why

[indignation]

Can anyone make some sense of this email I received earlier today from UB Payout Security Department? I made a deposit of $600 last sunday (3/25) to get a reload bonus, cleared it over the next few days, played enough to earn another 200 points or so after clearance, and then requested a cashout of $800 on thursday night(3/29). What have I done wrong, if anything?

[ QUOTE ]
Dear Sir/Madam ,

We have recently been experiencing an increase in bonus abuse on our
site and our fraud department has been forced to perform security
verifications to minimize this activity. After reviewing your account, it
appears that you are collecting hours in order to convert your bonus
dollars to real money and your earnings are not related to game play. This is
a form of bonus abuse and it is not permitted on our site and if these
patterns persist, your account will be permanently closed and your
balance will be confiscated.

Please send us a copy of photo ID along with an explanation in order to
further investigate your account. Your account will remain closed until
the investigation is complete. Our Fax number is 1.800.783.9366

Thank you for your co-operation.


Nolan
Payout Security Department


[/ QUOTE ]

I haven't sent them the fax yet but I plan to. Although I don't see what a picture ID has to do with the issues raised in the email. And what do I write in my "explanation" if I don't know what I've done wrong? I've never run into a problem like this so any advice would be appreciated. Thanks.