I have a Casio ctx700 that I received supposably new about 10 days ago and I noticed with quite a few of the drum patches some of the keys make no sound at all...on one of the drum tone patches 23 keys played no sound. I can understand if one or two 3 or so keys on some of the patches didn't play anything but 23 keys on one patch that play absolutely nothing is a little much...is this unit malfunctioning?..can't get a response from casio so far...