When utilizing toll-free number SMS, there are a few "best practices" to keep in mind:

• Callback numbers and delivery numbers must match. If your SMS mentions a phone number for customer callbacks, your delivery number must match (the number that the SMS was sent from).
• Messaging should not be aggressive or threatening. As with any customer interaction, messaging should not any type of foul language or threats. Be mindful of how your message could be construed.
• Volume should be distributed throughout the day to avoid spikes. With any outbound campaign (whether SMS or Voice), volume of messages should be spread out throughout a work day. This will allow for consistent engagement and will avoid temporary spikes in activity.
• Opt-in is necessary. Customers always have a choice on if they agree to receive an SMS. If they no longer wish to receive them, they have the option to opt-out.