You need them to send you the player with the dictation then you can convert to .wav. Mine it was VED1_Mini Player but it changes based on the model. The easiest way is to have them send you a copy of the Panasonic Video Editing software that came with the recorder.
I spent a long time trying to figure it out without having to go that far. Panasonic proprietary format just makes it difficult.
Panasonic is Okay with making copies of the miniplayer. They could send you the file and miniplayer together and you must put them in the same directory.