New India Assurance — insurance claim denied beyond the policy terms and not giving back my documents also

My health insurance claim 14996756, they have rejected. When equivalent clauses for claim consideration stated, they totally stopped responding/looking into the things.
Then, i requested them my documents back, so that i can apply for tax exemption. They have raised ticket 2718832. There are so many days completed, i didn't received my documents back. For any communications on this subject, they not at all respond.
They have very poor grievance system and customer requests lookup.