If you have any questions about this than add me on skype - Naziwalrus or add the seller - rulewarrior.
When you send a Friend request say " I need you to upgrade my spotify account to premium, referred by Aneesh "
These are not cracked accounts or codes. You give me the accountassword and a prepaid visa card is used for the member ship.
I don't know how this exactly works as im just reselling for a friend. But you can either get a pre made account or use a personal account. But i can guarantee this does not use Carding.
add rulewarrior if you need a detailed explanation .