SearchStax pay-as-you-go billing is based on the calendar month (first day to last day), with credit-card charges issued after the month ends. No one pays ahead. For this reason, refunds are rarely needed.
Clients often have deployments under multiple SLAs, where some deployments are under contract and others are billed to a credit card. Billing errors can sometimes occur and we will correct them as quickly as possible.
Be advised that credit-card refunds usually take about three banking days to get from us to you. We have no control over this delay.