I have been an AT&T/Cingular customer for about 9 years, and i have had an iPhone 2G for about a year and a half. I have wanted the iPhone 3g since it came out but didn't want to pay the 3g prices since i don't live within 150 miles of 3g service. So this week i bought a 3g iPhone off of ebay, and jailbroke it activated it, and popped my sim in. I left my data plan the iPhone 2g $20 plan that has unlimited data, and 200 text. Everything is working great(except my screen seems more yellow than my 2g), but today i got this text:

"Your data plan is ineligible for iPhone 3G. To prevent excess charges and enable visual voicemail, contact your telecom manager or AT&T"

My question is as long as i don't use 3g data they can't charge me any extra right? I don't care about visual voicemail as i have never used. I just want to make sure that as long as i just continue to use edge data and don't use 3g my current data plan will cover it right? Thanks in advance.

P.S. If anyone knows how to change the screen to not look as yellow please let me know. The only thing i can find is that updating your firmware should get rid of the yellow but did nothing for me. I'm on 2.2 firmware by the way