Originally Posted by Michael O

To ensure you actually own the card /account and to prevent people submitting the same cards for multiple accounts.
Zombaio process thousand and thousands of credit card transactions every day and if someone think that we will compromise their Payoneer/Paxum account and risk losing our core business than they are free to not take us up on our offer.
We ask for a partial card number and no CVV2 which means there are 10^6*1000 = 1 billion different combinations of guessing the card number and CVV2.