I’ve called several companies and none of them do this type of work. Who do I need to get in touch with?
A certified or qualified radon mitigation contractor will be able to address radon related problems. The EPA offers links to help find radon contractors in each state. Each state will have a State Radon Office: http://www.epa.gov/radon/whereyoulive.html
Some states require contractors to be licensed at the state level while others require a certification from an independent radon mitigation training class.