Incoming texts also cost one message each: when a customer texts your number, Sprwt stores the message and deducts the per-message rate, logged as Received SMS. Other non-obvious deductions are segment corrections — if the carrier reports that a sent message used more segments than estimated, the extra is charged (logged as Sent SMS). Conversely refunds (Sent SMS Refund) add money back when a message fails or when a segment correction lowers the estimate. Open a sent message in History > Sent to see its Balance History table (Log ID, Balance Before/After, Amount, Reason, Date), or check Reports > Sales Reports > SMS for a report of purchases/refills and message charges over a date range.