Abandonded Safe Deposit Box

We have a safe deposit box that has three owners. Two are deceased, the third has stated she has no keys and paid us $150 to drill the box. She refuses to come in for the drilling. She told us the box is empty (although she has never been in the box) and refuses to come in. Can we drill the box with out her? Last entry was in 1996. What if there is something in the box? So many questions. I can't seem to find any quidence for when the customer says "I don't want it"

Scroll down to Section 760.30

http://www.treasurer.il.gov/programs/cash-dash/pdf/act-rules.pdf