I recently purchased a used Yamaha MX88 online from Guitar Center. They shipped it to the Guitar Center store near me in Greenville SC. When I unpacked it at home I noticed the top and bottom chassis didn’t fit securely in back and flexed apart when I picked it up. I just thought that was due to cheap construction. There were a few keys that would occasionally stick but that seemed to get better after playing it a while. I didn’t think any more about it until the last week in August when I moved it from my desk to my keyboard stand. I noted the poor fit of the chasis again and decided to take a closer look. I shined a flashlight at the back of the keyboard, at the gap between the top and bottom covers. I was shocked to realize that almost all of the screw mounts on rear of the top cover were sheered off. I immediately got a sick feeling in my stomach. I’m now wondering what else is broken up inside the keyboard. In addition, several keys are sticking again. I felt more secure buying used from Guitar Center than an individual on eBay. I’m worried now that this was false security and now I’m screwed!! Is there any help for me or am I just out of luck!!