Urgent! Multi-Demo Error Concern!

Hey. I just purchased this theme and it’s requiring me to purchase a license to use a demo. I am creating THREE subdomains of the same site and using three different themes, because each sub-domain will look different. Am I required to purchase the license two more times? Please can someone contact me. To clarify, I am building one site and there will be two sub-domains. One will be for kids to read, teens to read, adults to read so will use three different demo looks but will be just one site – just different looks for each sub-domain because we need to separate looks. How do I use my license on all? Was told that I wouldn’t have to buy anymore licenses but am running into an issue with install.