Try the app at bitpim.org With a USB cable and bitpim, you may be able to dump all the text messages to a spreadsheet.
And just a bit of advice...if your business is so dependent on archiving electronic messages, it may be worth your investment in a device that will do just that. And I wouldn't save 2 years worth (I'm not even sure the Touch can save that many; my Voyager would delete the oldest if the "inbox" got full).
The Env Touch can hold up to 50 text and 50 pix but when I get a really important one such as a phone number or address I lock it in the phone so it doesn't get deleted. And will be able to access it at a later time in the future.
But how would I be able to do this if al I get is a blank screen when I have the phone on? My screen is 100% blank which is the problem I am having. And the text messages are an important part of my buisness.
Once you plug the device to the PC with your USB the software can access the devices data.... The software access the phone not the screens data and can copy the data if its there.