If your payment using credit card is declined by gateway anti-fraud check, you can purchase bitcoin using your credit card at https://www.coinbase.com and pay for Boxxer
How to buy bitcoin using credit card from https://www.coinbase.com
#1. Goto https://www.coinbase.com and enter your email id and get started
Once signed up, log in to the Coinbase app, select the Menu icon near the top-left.
Enter the amount of digital currency you would like to purchase.
Select your card as the 'Payment' method.
Confirm the information entered is correct and select 'Buy Digital Currency'.
here is the youtube video on how tyou can buy bitcoin with credit card