Don’t worry. Most times when a card is declined, it’s because some details were entered incorrectly. Try re-entering your credit card details, ensuring every detail is correct.
Also, double-check that your card is one that our payment processor accepts – we can accept payments from most major card providers, but there are one or two exceptions, see: What payment methods do you accept?
If you’re still unable to place an order, we recommend trying a different form of payment, such as a different card, PayPal, or Amazon Pay.