I did contact them and pretty much made two suggestion.
1. Lower the price or offer refunds. ie, charge what is worth especially if you're not going to support it
2. Update the product and make it work.
I assumed they'd go with 2, but the pretty much told me to contact Apple about a refund, which is the same as saying they have no plans to fix it.
The issues I'm having are pretty simple, its just really slow to respond, when you rotate from landscape to portrait, it takes 10-15 seconds to appear, and it doesnt' remember your place so you have to scroll. Pretty much any time you press any button to preform any function it takes 10-15 seconds to respond. Its really really slow.
I think you have too many "chat logs" saved on the app. That happened to me on my iPhone 3G, I deleted most of it and boom the app is fast again. Try it and see if it works.