A lot of websites are no longer supporting Visa/MasterCard because credit card companies are big fucking babies. You can buy BitCash prepaid cards on Play-Asia and use those instead.
https://www.play-asia.com/search/bitcash
Make sure you look closely at the prices so you don't overshoot or undershoot the cost. For example, this set was 2860 yen (2500 yen base price, 150 yen for tax, and 110 for BitCash fee), so by buying the 3000 yen prepaid card I only "wasted" 140 yen (or slightly less than a US dollar).