Are there other groups or organizations you can get involved in? If there are, find a local chapter and attend a meeting. Introduce yourself to the organizers and let them know you want to get more actively involved.
If there isn’t a local chapter find out how you can create one. With some of the larger organizations, you might need to be a little persistent. Don’t take it personally. Many organizations are short staffed and may not have the resources to get back to you right away.