Of course, free and open source tools don't have customer support services, but they have developers. Often, you can contact the developer directly and ask your questions, or even share (if possible) the data source problems you have with them. This helps developers to improve their tools and help the community.

Some tools, such as The Sleuth Kit and Autopsy for example, have mailing lists: you can ask your question and the developer or active users will answer it, as shown in the following screenshot: