iPhone users on the MacRumors Forum and HowardForuns are reporting that they received an over the air update that pushed the correct data and MMS settings to their phones. The new update is Carrier Update 15.6. To get it go Settings > General > About on your iPhone and see if there's an update available. Some users reported that they did not get the update until after they updated iOS to 7.0.3.
Warning: the update configures the phone to use the "new" tfdata APN. If your phone uses the "old" att.mvno APN try to avoid downloading the carrier update as it will break data. If you do get stuck with the update, you can get data (but not MMS) working again by downloading a profile from unlockit.co.nz. Or use the SIM swap method to fix both MMS and data. For more about the different APN's and alternate ways of setting up data see, How to Setup Straight Talk & NET10 Data and MMS on Android, iPhone & Windows Phone.
Even with a new SIM there are other problems with the new tfdata APN. Push notifications for services like iMessage, push email and Google Voice are reportedly delayed by up to 15 minutes and PPTP VPN connections no longer work.
Once you get Carrier Update 15.6 data and MMS should work without you having to do anything, If it doesn't, try the following:
- If you previously set up custom data profile for Straight Talk or NET10 using the SIM Swap method or by downloading a profile from unlockit.co.nz or iapnupdatetfdata.straighttalk.com, go to Settings > General > Profile and delete it.
- Turn the iPhone off and back on
If you call customer support they will probably tell you that reprovisioning is not possible. But one HowardForums user reported that he was able to get his account reprovisioned by calling repeatedly and asking that his issue be escalated to a "more technical" department. If you want to try that I recommend using NET10 and Straight Talk's "Executive Resolutions Dept.", a possibly Miami based but definitely more competent call center, at 1-305-715-6500 or 1-800-876-5753. Executive Resolutions hours are Monday – Friday from 8:00 AM to 7:00 PM EST. It's best to call early in the day, once Executive Resolutions gets busy calls roll over to the regular support centers.
An easier but more expensive way to get your account reprovisioned is to buy a new SIM from www.straighttalkbyop.com or www.net10byop.com for $6.99 with free shipping. When the SIM arrives switch your account to the new SIM online or by calling CS. New SIMs get provisioned with the new APN.
The new carrier update should make it a lot easier to use an iPhone on NET10 or StraightTalk. It should also mean the end of having to redo settings after every over the air update.
Update: the Staight Talk/NET10 iOS carrier file has been updated again to 15.7. The only change seems to be that "3G" instead of "4G" appears in the top status bar when connected to HSPA+ data.