Issue of caste and abc certificate

I am a resident of hyderabad telangana state since my birth. My parents have been residing in hyderabad since 38 years. Before 38 years they resided in rajasthan. I have applied for BC and obc certificate in the concerned mro office in hyderabad. But the concerned official is telling me that you can't be issued BC/obc certificates as your parents originally belong to rajasthan.can they do so? My father is a gold Smith by occupation. We belong to backward class community group b serial no. 21.my sub caste is vishwabrahmin. Inspite of producing required documents they are denying me issue of my caste certificate saying that we can't issue caste certificates to hindi speaking residents of telangana state.. Only telugu speaking residents can claim their caste certificate.. Is it so.....? I was issued caste certificate in the past in the year 1998 from the same office in hyderabad . But the concerned official is denying that certificate validity also. Kindly provide me the necessary guidance... As soon as possible..