I join my voice to those who suffered from Payza, they can easily take your money saying it comes from fraudulent sources and that there is nothing they can do about it but to advice you to stop shipping of goods or the service you are providing to the fraudulent party.
I also never heard of this $500 minimum transactions to get verified, but my account was verified since 2011 so I can't really know about the current rules.
There is no $500 trade requirement. I managed to verify my account when I did not make a single trade. Regarding fraudulent goods, they do not care if anyone loses their money and can chargeback even after months.