Each SendHub plan comes with a specific amount of usage available for different features. This includes total monthly messages (unless you are on a plan with overages), maximum recipients per-SMS, number of API calls, and in some cases a limit on the number of lines you can add.
If you know you're out of messages, or received an email saying "Account Limits Reached", you may need to upgrade your plan, or wait until your next billing cycle begins. Another option is to purchase one-time messages.
For SMS plans the cost is 0.05 cents per text, and on MMS plans the cost is 0.06 cents per text. To purchase one-time messages you can click the gear icon at the top right of your page, go to My Settings, then scroll down to ‘Buy One Time Messaging’. You can select the number of messages required from the drop-down list and click on buy.
Voila! It’s done.