IPhone 3G running 3.1.2 still having intermittent loss of data services

Question

My wife's 3G is randomly indicating that she has no internet connection, so she can't get data and/or send SMS messages. Even though she's in a spot at work where it used to always work fine.
Her 3G has the latest 3.1.2 firmware and has gotten all of the updates from 2.0 to 2.1, all the way up to 3.1.2.
I think people that have the earlier 3G's and have gone through multiple updates seem to be having the most issues.
Let me know if anyone know of some way (ANY WAY) to fix this. Again, she has a 3G running 3.1.2 and has applied updates from 2.0 on up to 3.1.2...with instability issues showing up first with 3.0.
I personally have a 3G (just as old) and have gone through almost the same updates, BUT...I didn't update from 3.01 to 3.1. My 3G began getting squirley (Safari crashing with muliple tabs open and general lag doing text entries...stuff like that) after I updated to 3.01 (or was it 3.0?), so I held off doing any more updates until the coast seemed clear to do one. I'm glad I held off as the 3.1 updates made matters worse for my wife and many others.
3.1.2 still has issues. I'm sure the phone hardware is fine, but installing multiple updates over each other seems to create instabilities.

Answer 1

Here is my post when I first started having problems with the 3.1 update:
*+Model: iPhone 3GS 16GB+*
*+Location: Los Angeles+*
*+Firmware Version: 3.1+*
*+Symptoms after installing 3.1:+*
*+Battery Issues - Since upgrading to 3.1, battery life has become dismal. If leaving the house in the morning at 8am, by 2pm or so, phone is down to 10 percent or less with minimal to no browsing. Before, 3.1, iPhone would last at the minimum 24 hours with medium browsing and multiple text messaging.+*
*+Texting - Text message sending is non-existent. All text messages fail on send. To alleviate situation, I must reboot phone and then it works for an hour or so. Before 3.1, text messaging worked flawlessly with text message failure once every 50 or so text messages.+*
*+Reception - Signal strength has gone from great to really bad. I've always had reception at work. Now, nothing. Calls don't come through and go straight to voicemail. Before 3.1, reception was perfect. No dropped calls, no reception problems, no phantom calls.+*
*+Syncing: Multiple problems trying to sync phone to computer. "Disk cannot be read" errors as well as freezing on initial sync. Before 3.1, never had syncing issues.+*
*+No freezing issues or shutdown issues experienced as others have stated.+*
*+I went to St. Louis this past weekend and discovered that to alleviate the situation, I have to turn off 3G (Settings>General>Network). Phone is now only on EDGE network. Works fine but it shouldn't be like this. If 3G is turned on, iPhone moprhs into doorstop/ throwing weapon.+*
*+I don't believe the phone itself is the problem. It's firmware based. Seems like there's a conflict with the firmware and the 3G network. I am an end-user and do not have a technical background.+*
After upgrading to 3.1.2, I'm still having the same issues. The only way I can get my phone to function is by disabling the 3G. I'm currently using Edge. IN laymans terms, this is ********.
Message was edited by: prince.buster