To register your SMS Magic Converse account for the first time, follow the steps mentioned here.
Salesforce users can have multiple sandboxes. Each sandbox can be linked with the SMS Magic package; i.e., each sandbox can be registered with the SMS Magic package.
In case the sandbox is refreshed, you can re-register your SMS Magic Converse account to get the same configuration and settings that you had with your original account. After refreshing the sandbox, the org ID changes and so does the settings of the new org too.
To inherit the settings of the original sandbox (before refresh) with the new sandbox (after refresh), you will have to follow the same registration and configuration process. For this, you need to connect with the respective account manager/CS team member and register your converse app with the same settings, and configuration that of your original converse app.
So, to get the SMS Magic Converse package activated in your refreshed sandbox you need to get in touch with your respective account manager or connect with the customer support team at firstname.lastname@example.org and follow the same registration steps mentioned in the link above.