There may be 2 reasons for this. 1) Probably the information you have asked is having more like questions or asking many questions more than 10 etc or for some questions/requests they may not have information as per the record.
2) Sometimes they may not reply wantedly / willingly.
I had applied for rti on 22 June,2019. They send back a confirmation letter that they get amount of rti. but still they don't send answersheet copy. Please, suggest me what to do next?