Hoiio neither sees nor stores your credit card details. When you are making payment with Hoiio, you will be redirected to the payment gateway (WorldPay). The payment gateway will then authorize the payment to Hoiio. 

The auto-topup and subscriptions in Hoiio works by establishing a secure electronic contract with the payment gateway when authorized by you. Compared to a bad security practice of storing credit card information, a thief or hacker cannot make payment to themselves from such contract. Any time you decide to stop payment to Hoiio, you can do so from the user portal, [Settings] -> [Credits] -> [Payment Account], and delete the associated payment account. However, this will cause future auto-topup and subscription to fail, thus disrupting your Hoiio services. If you wish to disable auto-topup or end a subscription, we recommend you to do so by not deleting the payment account.

No one in Hoiio ever sees your credit card details. Never give our your credit card details to anyone who claims to be an Hoiio employee.