Money donated for a deceased individual's legacy gift has been spent elsewhere. Pennsylvania, 501(c)3 corporation. Where to start?

What is the 501c(3) organization? You say that a gift was made intending that it fund a gift to a specific individual's estate, but charitable contributions may not be directed to any specific individual - that would make it a personal gift, not a charitable donation. I suspect that you may not understand how the organization makes decisions on how it grants money to recipients. We can look into this a bit deeper if you tell us the name of the charity.