ok, so I have tried every configuration of settings for my apn's. I just spent 2 hours with ST techs who finally informed me my phone wouldn't get MMS or Data because "it's from China, and we don't support foreign phones." well, alrighty then. I got mad and boom, I had data and mms working in 5 minutes, no problem. Here's where I started and what I did:
I purchased an unlocked phone from GSM Nation in Sept,. a Lumia 1020. From the start had issues with mms, then data too. I purchased my sim from ST directly. This is what I did differently:
My phone, upon delivery, had in its Settings an ATT option. I never used it, thinking i HAD to input setting apn's and proxy numbers under ST . I always created a new name of ST and input my info that way. This time, I said screw it and chose the ATT option that popped up when I opened "access point" on my phone. Here's my settings, and once I put them in and rebooted, everything worked perfectly.
name: Alternate ST (LOL, in case it didn't work)
Access Point Name: tfdata
Proxy: 66.209.11.33
Port:80
Network:Ipv4
MMS APN ; tfdata
Proxy address:66.209.11.33
Port:80
MMSC address; mmsc.cingular.com
network type: IPv4
And that's what worked for me. I did a happy dance, since I've had the phone for 2 months and couldn't get it to work right. If anything changes or quits working, I'll update that too. I almost switched to Gophone over this; this has been incredibly frustrating. But I absolutely love my 1020 and it was worth it if it solved the problem