If possible, can I pay with a prepaid card such as a Google play card or Amazon gift card? I don't have a phone number so I can't use Paypal etc.

I tried to upgrade my ATS-25X2 from firmware version v5.3 to v4.2, not knowing that v5.3 is the free version and v4.2 requires purchase.　I suppose I can revert the version, but I want to use the new version, so please let me purchase a license key! I am in Japan. I don't know what payment methods ar...