MISSING ASSISGNMENTS

This is not the 1st time my wife assisgments is gone missing from the drop off box in front of the security gate .we have taken pictures of the physical assisgnment before handing it in.We have dropped off 2 assisgnments that was due on the 17th .the 1 has being recieved & the other has not BOTH HAS BEING DROPPED OFF at the same time.NOW WHAT DO YOU DO.Submit online? it works when it feels like, dropp off it goes missing.WHAT DO I DO TAKE LEGAL ACTION <br>