I am lost
If an address (or the user of a post office box) changes, the new resident is
supposed to mark any mis-addressed mail as undeliverable and return it to the
post office.
Sadly, many recipients just throw such material in the garbage. Your money
may not have been taken .. it might well have just been thrown away!
The suggestion of writing the US Postmaster General is a good one. This will
trigger an enquiry from the postal authorities, and *possibly* you might find
out what happened.
That's one of the problems with small software houses, and shareware. The
material often comes from people who move a lot (students?) and it can become
difficult to track them down. This is especially vexing when you have
"crippled" shareware, in which case you would have sent money and still have
only a package of limited usefulness. (No suggestion that this is true of the
Greg Grove package).
–Jim