More than 250 Marylanders with developmental disabilities were “erroneously” disenrolled this summer from Medicaid programs that gave them access to community services and other care, leaving family members frustrated and angry as they try to regain services for loved ones. “It feels like he somehow fell out of the system that was supposed to work for him,” said Frederick resident Patricia Marshall, 67, of her grandson’s sudden loss of his Medicaid waiver.