I don't think it can be "fixed" the way you want it to be, so I'd stop trying.
However, if you hadn't taken it apart, I don't think it needed to be fixed. It is a pretty typical top for a beginner, and could have just been treated as done and used for quilting practice when you bought it.
Since you have taken it apart, just put all the contents in a bag and donate it to goodwill. I wouldn't trash it- as someone may be able to use it; but I wouldn't use your time on it either, as you will never get what you want out of it.