I'm so sorry for what you've experienced so far with PA. But if you've read this thread, you'll know you aren't alone.
You may get no response to your email, but there's a good chance you'll get an even snarkier reply than you received the first time. If you do, don't take it too much to heart--this is how they treat all their authors who persist in asking reasonable questions.
The problem with "kind of" re-writing and re-titling your book and then trying to market it as new isn't with PA. As I noted above, they have so little care for and knowledge of their authors that if you did this, it's likely they'd never figure it out.
The problem is with a new publisher. Publishers don't want books whose rights aren't completely free and clear. A reputable publisher won't be willing to take on a book whose rights are contracted to another publisher--even if you've made changes to the text.
Could you make changes and market the book as new and just not mention that the original book was contracted to PA? Sure. But if your new publisher finds out (and the odds that they will aren't small, because everything on the Internet is eternal, and publishers and agents do research their authors) they would not be happy--to put it mildly.
I know how painful it is to abandon for a book that you've worked so hard on and hoped so much for. But the best thing for you to do now may be just to move on. Write another, even better book. Market it to real publishers. Success is the best revenge.