If it freezes up your phone again and you know for a fact the app is defective you could always go to the app in the marketplace and give it a one star rating, explain what they need to fix.
Just say "<rate 1 star> This app freezes my phone when I use it, I am using it on my <phone name" it will allow the developers to fix the problem and make sure it works for your phone if it's your models issue, it's better to tell the developer the error instead of trash their creation; they could improve their app that way.