Before I start. I'll point out that I've no connection with the company your having grief with, and I'm not even a N364 owner.

What I want to know is, how do you know the disks are fautly?
Do they load direct into the N364, or are they loaded via system exclusive over MIDI usind some computer software.
To have 1 faulty disk is unlucky, to have 2 is very odd indeed.
Where any instructions given with the disks?
Did the N364 have to set on a certian MIDI channel?

Just interested.....