Any ideas?

I had a bad weekend with my wall mounted machine. It is in a 3 year old custom cabinette made by some folks in Idaho that I thought made a good one.

It started to come unglued at the top and I couldn't figure out why at first until I loosened the bottom two bolts and the whole top of the cabinette ripped off with the one by 4 still attached to the top.

The top was held on by glue and about 8 small staple thin nails. I snipped them off and I re-attached the top with 24 staples from a staple gun and a dozen brads through the top.

I then set out to build a french cleat using a 20 inch one by four and two cleats from a one by 8 each 8 inches long. I did it that way to leave enough room so that I could get 4 3.5 inch #10 screws into the stud over the outlet.

Then the fun began. The cleat was too deep for the 1 by 4 near the top and the back of the machine was right against the wall. So, I found a piece of plywood and cut it 8 X 21.5 to cover the whole back and give me the whole two by four to screw into it. But it is now about 6" higher off the floor. It worked great, too great and this is when I figured out my problem.

It looks like years ago before we got the house there was a window where I put my machine and there was no stud only plastered over lauran paneling.

It is holding but I'm afraid to play the thing (bowing out). I could try and screw it back into the wall but I can't think of a way to do it and keep the french cleat.
I also do not have any other wall I could put it. So short of pulling apart the wall is there anything I could do?