Star Health And Allied Insurance — serious negligence in customer support.

I am a health policy holder of this company. I called the customer support service for my claim at the time of hospitalization in a network hospital of this company, they massage me back that your claim is received. Within one hour they rejected my claim by the policy term basis and emailed the information to the hospital concern, but not to me. Hospital adminstration informed me next day that star health has rejected your claim and you have to pay by cash now. After then company customer service informed me that your claim was rejected yesterday. I asked them that why didn't they massage me or emailed me at the time of rejection of my claim. No satisfactory answer has given. What can i do against this negligence of star health insurance company.?