MMS Problem. APN Setting erasing

[bpolunin]

OK, I have been battling this for weeks and can't find a solution. OK, I have 3GS with 4.1.2 on TMobile. Everything works fine and then after about 4 hours, the MMS APN erases. I go into settings input it again, get out, back in and its gone. I have to reboot the iphone to enter it again for it to stay. Then after about 4 hours it's gone again.
What gives? Anyone seen this? Any idea how to fix? I already tried Tmobile MMS Fix from cydia.pushfix.info

PLEASE HELP. PULING MY HAIR OUT

[ericc54321]

I am having the same problem also.