Discovered an employee is OIG excluded – what do we do?

I was doing regular checks on our contractors and just discovered one of our contractors has been OIG excluded  and we weren’t aware of it until now. What is the sequential way to handle this situation? Should we terminate or end the contract immediately, or can we still find a resolution? Since we bill Medicare, I am concerned about potential liability. Has anyone else encountered this issue and what did you do to remain compliant? I would greatly appreciate your advice. Thanks!