Additional Proof: 

due _______________________

You must get some kind of additional proof that you were at your agency.   This can be a brochure that they publish.  It can be copies of forms that people fill out when they use your agencies' services.  It can be pictures that you take (with permission, of course) when you are volunteering.  The additional proof can be anything that your agency gives to people that are at the agency.  This proof is turned in at the end of your volunteer time.