If you are constantly getting an AVS (Address Verification System) payment declined error, it is usually due to a foreign transaction or the underlying bank does not support AVS. We suggest you do the following (the easiest solution is to checkout with Paypal):
1. Call your bank and see if the address matches or is identical and make sure they support AVS.
2. Checkout via Paypal instead - oftentimes Paypal handles foreign transactions better (you can checkout as a guest with the same credit card. PayPal account is not needed)
You may also want to watch this tutorial on How to Resolve AVS Mismatch.