Tahsildar not releasing file

We have land whose ownership has now come other dispute. We genuinely believe that the other party's claim is bogus and so have been fighting it out in court. Following a trail of documents we have found out that there is a piece of document which will remove any doubt about the rightful ownership of this land and this file is crucial for our next hearing in court to go well. We applied for the file through the RTI act. The said file is sitting in the Tahsildar's office and all our honest attempts to obtain it have been futile. For the last week my father has been visiting the office every single day but he is always on leave or too busy to meet. His one signature will release the file and there is no legal reason for him to not sign yet he is delaying. We do not have much time and need to act immediately. What action can we take, who can we approach so that the Tahsildar releases this file. In case there is nothing to do to get the file before monday (4/08/14) , on what grounds can we ask for an extension in the court. (this would be the second extension we are requesting). All help is truly appreciated.