The Refillable Usage feature offers subscribers a way to avoid high overage charges. When a subscriber’s Base product has been depleted, the Refill product is automatically added to cover a new increment of usage. This usage can be voice, data, text, or currency. Carriers can also create Refillable Products for different types of usage, such as one amount for domestic airtime and a different one for international airtime.
Refills are used to apply charges when the base allotment is exceeded. They are active for the full bill period regardless of when they are added (started at the bill period start date and ended at the bill period end date) so prorating does not apply.
Notes:
The refill product must be set up before any discounts can be built. This is because the SKU/SvcTypeID associated to this product will be used to associate the product to the discount when the discount is configured.
Refills MUST be created as products and NOT packages. Also, a unique refill product is required for each refillable discount offering. Refills cannot be reused across multiple refillable discounts.
For comprehensive guidelines on setting up and using this functionality refer to the knowledge article here.