Log in to the Sinch Customer Dashboard and select the Billing management option from the Billing menu on the left panel. The Billing management page is displayed:
In the Low balance management section, enter a minimum balance for your account in the Low balance threshold field. If you balance falls below this amount, then you will be notified by e-mail. Please make sure the amount you specify is low enough but allows your account to be recharged without consuming all the balance - to avoid getting your account blocked.
To enable automatic recharge, select the Automatic recharge option and set the amount you would like Sinch to charge your selected card (when your balance falls below the specified Low balance threshold) in the Amount to add field. Click SAVE.
Note:This functionality is only available for prepaid accounts.