any one can help me explain it? about registeration

i'm not american,and some company like godaddy register.com 1and1 they didn't allow the people in my country to buy the domain with coupon, but i want to buy some domains with coupon, how did they check it out that i'm fraud? and how could i buy the domains with coupon? sometimes i bought the domains but two days later they delated it, it's really awful.
guys can you give me an advise?
further more, i bought the domains with virtual credit card or paypal,because i need a little more domains, but i have only one credit card.