Here's what happened:
April 18th, 2013 (one year ago), you requested a $605 withdrawal, which was won based on a cash-back bonus of $249.38. That cash-back has a 1x max cash-out, so at most you would have been entitled to was $249.38. When you requested your withdrawal, you received notice that we would need certain verification documents, which we never received, so May 5th, 2013, your withdrawal request was cancelled and the $605 was returned to your account.
Then on April 15th, 2014 (this year), you requested a withdrawal of $254.49, which was approved, April 22nd. The approval amount was $249.38 (that 1x max cash-out), with the remaining $5.11 removed from your account.
You had previously built up spins on Aztecs Feature Guaranteed, using the original $249.38, which you never triggered. Following the April 22nd withdrawal, you went into the Aztecs slot, triggered the feature and won $148.61--you were able to build that up to $500, which you then attempted to withdraw. The problem with this is that you had amassed those spins with the original $249.38 (back in April, 2013), and you've already received the max cash-out on that money.
It is because of this that the funds were removed from the account and we have correctly denied your subsequent withdrawal request.
I hope this clears things up,