On Settings > Billing, the SMS Credits card shows your current balance plus two usage stats pulled from your account's SMS history: Total sent is the running count of every text message Sprwt has sent for your account (marketing, order notifications, etc.), and Last message shows the content of the most recently sent text. They are informational only - use Buy credits on the same card to top up, and the SMS Wallet page (opened from there) for the full balance, rate and auto-recharge settings.