We understand you are getting an AVS mismatch error and here's a couple reasons why:
We are lumped under Tobacco Sales (a high-risk business). If the address that your bank has on file does not match exactly (if you are writing Street instead of 'St' or capitalizing a letter that is not capitalized) the card issuing bank will decline the transaction immediately. In addition to this, if it is a Capital One Card. Capital One has a company policy to not allow ANY transactions to go through for electronic cigarettes.
If you happen to be using a MasterCard, we highly recommend calling your bank to ensure they are not putting a security hold on the transaction. As mentioned before the products intended for purchase are considered Tobacco Sales and can cause a high-risk flags with the bank.
We are unable to push the sale through on our end and this is an issue that will need to be discussed with your bank.