Card payments go through Stripe. Your card details never reach Reloot.
Checkout takes payment through Stripe. Card, and Apple Pay or Google Pay where your device offers it. The card form is Stripe's own; your card number goes to Stripe and never touches Reloot.
If a payment is declined, the order is not created and nothing is charged. Try another card, or check with your bank. A first payment to a new business is a common thing for them to stop.
