MacShiny experience anyone?

So my wife gave me her MacBook when she upgraded, I'm only a few months in as a Mac convert and feeling my way around. One of the first things I noticed was how slow my computer seemed to run, I ran the ClamXV she had installed no issues, seemed to have plenty of free memory. I went into the app store and downloaded MacShiny, it seemed to get some of the best reviews. I ran in the initial time with what seemed like success, however subsequent attempts to run the app give me an error message along the lines of "oops, something seems to have happened when trying to run mach shiny, please forward to us so that we can help resolve the issue". Well, that didn't work, I received one response asking what the error message sent (information I'd already sent them). I waited awhile, no response. SO i emailed again, and again, and again. NO response. Now I look under purchased apps it doesn't show up there, I do a search for it in the app store it doesn't show up there. I've emailed countless times without a response. The icon still shows up at the top of my screen next to the bluetooth icon, but it won't run. So my questions are - does anyone have any experience with this app? If it's suddenly gone from the app store do I have any recourse with Apple or am I just out the $20 or so that I spent on the third party app? and if I can't get anything out of the developer or Apple does anyone have a solution or the correct way to uninstall? and finally, any suggestions on the best way to clean up cache, OS system, etc.? Thanks in advance.