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My customers are billed twice for the same period. Why is this happening?

What happens when there are changes made to a subscription with an advance invoice?

Summary

In Chargebee, when you make changes to a subscription (overriding the price, changing the plan/addon etc.) that has an advance invoice(current period), the Advance charges will be refunded as Credits.

Here’s is an example, that lets you understand this use case better,

1. Consider a subscription that has an Advance invoice. 

2. Now, when you make changes to the subscription say add or remove an addon or change the coupon or plan price then, the advance charges will be refunded as credits and a credit note is created for this invoice.

   1. You can “Preview” the changes before you make changes to the subscription and click Confirm. Below attached is a sample image of how the preview looks.
      
      

3. The credits get added as Refundable Credits which can be seen in the summary at the subscriptions details page as specified in the sample image below.
   
   

Note: Credits available under the customer will automatically be applied to upcoming invoices.

Here’s a video explaining the above scenario.

Related articles and Documentation

How to raise an advance invoice?

My customer’s invoice doesn’t move to a pending state. Why?