Massachusett-based Caritas Christi Health Care System has fired back at a former executive who sued the hospital system for slashing his severance package. In a court filing, Caritas Christi said it was justified in canceling a nine-month, $250,000 consulting agreement with Michael Metzler, the former president of Caritas's St. Anne's Hospital in Fall River, because he failed to promptly report a discrimination complaint.