This may be caused by the following.
▪ Delay in the credit card company’s billing
Depending on the closing date of the credit card company, billing may be delayed by 1 to 3 months following the month the service was used. Therefore, even after stopping use of the service, billing may continue for several months, but there will be no excessive charges if the cancellation process was executed correctly.
▪ The cancellation procedure was not completed
Please confirm the pixiv ID registration status of the canceled pixiv Premium membership. You can confirm this status from the "Confirm/Modify Premium Registration" Information in the "Settings" menu. Please try again if cancellation has not been completed.