Q: Why is my 3G not working?

Hi Shannen_,

I'm sorry to hear you are having these issues with your iPhone. If you continue to have issues with your cellular data connection, or the settings for cellular data do not appear to be sticking when changed, you may find the information and troubleshooting steps outlined in the following articles helpful:

Learn about cellular data settings and usage on your iPhone and iPad (Cellular Model) - Apple Support

If you can't connect to a cellular network or cellular data - Apple Support

Regards 

Hi Shannen_,

Thank you for using the Apple Support Communities; I'm sorry to hear you are still having this issue. If you have gone through the above linked articles completely without reaching a resolution or a direction for further troubleshooting, you may be better served by reaching out to one of Apple's other available resources for more direct assistance - https://getsupport.apple.com/GetproductgroupList.action

Regards