# Billing and credits: Help Center

> How credits work, topping up and invoices.

URL: https://landing.qa.scrini.ai/help/billing-and-credits

- [Are we charged if a call fails?](https://landing.qa.scrini.ai/help/billing-and-credits/are-we-charged-if-a-call-fails) ([markdown](https://landing.qa.scrini.ai/help/billing-and-credits/are-we-charged-if-a-call-fails.md)): No. Only completed tasks use credits.
- [Do unused credits roll over?](https://landing.qa.scrini.ai/help/billing-and-credits/do-unused-credits-roll-over) ([markdown](https://landing.qa.scrini.ai/help/billing-and-credits/do-unused-credits-roll-over.md)): Unused credits expire at the end of your subscription term. You can top up any time.