Doesnt work at all

I bought this app some months back. In the last few weeks I really need it and it doesnt work -- doesnt come up. I deleted the app, turned the phone off and on, and then downloaded it again. Doesnt come up at all.
I have an iPhone 3G and am wondering if it just doesnt work anymore because of upgrades? Why? Any ideas?
Ive reported the problem twice to the developers-- even left my name, phone number, and email address. No reply to date.
I also went to their website and left a note in their "contact me" section. No reply to date.
Can anyone explain this to me?

TinCanTeli about Grammar App by Tap To Learn, v2.2