AT&T Wireless IP Clue

Does anyone have an IP clue contact at AT&T Wireless? They have some sort of filter blocking most (all?) of 69/8 to their SMS email gateway, and even the AT&T Wireless NOC can't seem to find the problem (800-832-6662, option 6, ticket #1087071). I was leaning towards 69/8 bogon filters until I noticed that twice a day for about 30 minutes everything works.