Well that's frustrating! There could be a number of reasons why a credit card isn't working properly, including things like having an incorrect zip code or CVV number, and also because our credit card processor just isn't working properly, timing out or having a bad day.
But there's no need fret! You can try processing your credit card transaction through Paypal by selecting that option at checkout:
You won't be forced to sign into Paypal or create an account, just select "Pay with Debit or Credit Card" on the sign in page:
Hopefully this helps to solve the problem but please reach out to us if it doesn't!