You can wait until the 1st day of next month for the data amount to renew itself, or you can purchase additional recharge payment to unlock voice call limited service.
To unlock the *Voice Call Limit Service*, please follow to these instructions:
- Log in to *My Page* https://user.jpmob.jp/users/sign_in
- Select "Recharge" from the menu
- Apply for "Recharge Voice Call Usage: 2,200 Yen"
- Check the payment due date from the "Payment" menu
- Make the additional payment
Voice call function will be unlocked for your account right after you finished your additional payment.