Tufts Medical Center and health insurance provider Blue Cross Blue Shield of Massachusetts are back at the negotiating table after a tense month of contract negotiations. If negotiations fail, Blue Cross customers would have to find new doctors or insurance providers. The setbacks highlight faults in the state's health care system, according to healthcare advocates. Tufts Medical is the main teaching hospital associated with the Tufts School of Medicine. Tufts Medical and its affiliated physicians group, the New England Quality Care Alliance (NEQCA), announced on Nov. 15 that they planned to end their contract with Blue Cross on Jan. 17, 2012, according to a Blue Cross statement.