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If you are in Ci-en.

You can purchase DLsitePoint and DLsitePoint can be used for payment in Ci-en.

For details, please view the link below

支払い方法を教えてください – Ci-en

If you are in fantia.

You can select Charge COINs (Purchase at Tokyo Otaku Mode) when subscribing, and then choose to purchase at Tokyo Otaku Modeでチャージ.  

These methods should workヾ(•ω•`)o