Papers lost / misplaced in provident fund office

I have submitted Form No. 10 D under Employees Family pension scheme in January 2015 completed in all respect enclosing therewith original scheme certificate by speed post. since I did not get any response even after several e mails I asked the provident fund office about my pension claim through RTI. I got the reply from the office that they have not received the form till today. I put a complaint with post office web site. The answer from post office received that they have delivered the envelope to the addressed and they have mentioned the date of delivery also. I have requested the post department to provide me the computerised delivery report sealed and signed. I have also requested to provide signed copy of run sheet on which postman takes signature of adressee. which I can get from post dept.Now I want to know how to proceed. If I prefer first appeal under RTI they may confirm that form though received were misplaced somewhere.which does not solve the problem of getting pension. If I want to resubmit form 10 d once again my application will not be processed since I have no original scheme certificate now. . Kindly advise.