Since FreeBurn is not a commercial program, there is no toll-free number to call if you have a problem. However, if you have a problem with using the program, you can try one of the following options to get help with FreeBurn:

Try the FreeBurn Users mailing list
You can try send a message to FreeBurn Users mailing list to get help. You can also try to browse the list archives to see if your question has already been asked and answered.
Post a message in the help forum
There is also a help forum where you can ask a question as well. This may not be as efficent as getting an e-mail sent to you, but you may have some success with it.
Submit a bug report
This isn't really getting help with using FreeBurn, but if you run into an error please submit a report on our bug tracker. This will enable the developers to find and fix any bugs that come up in the development of FreeBurn.