NIOS — certificate not yet issued

I wrote 12th exam in 2018 oct and passed.. Study centre told me that the certificate was damaged and they are waiting for its reissue. They asked me to contact regional centre. I called there but no response.. I went to the regional centre kochi, and reported them the problem. But they told me that they have send the certificate to trivandrum study centre. Again i called study centre but they are repating the same and wants me to wait. They says that they are helpless..
In regional centers, no one is picking the phone and study centre is just asking me to wait. Pls help me to get my certificate..