Help Instant Messenger functionality

[Kittenkawa11]

now, this seems to be a repeating problem, I'm a Tier 3 Tmobile Employee, and will not state any specifics, however, for those who use Instant messengers, either unlocked, or with a different internet plan, seem to be having problems with their Instant messengers giving a message like 'sorry, the phone number cannot be read from your sim card.' after doing some research, this appears to be a conflict of the APN. the APN for these programs I believe to be Imbedded within the instant messenger software, meaning that the network is declining the connection without proper access to the specified APN. I'm wondering if there's any way to manually configure/change the APN on these applications without using any 3rd party or downloaded app. any information on this particular matter would be appreciated. either confirming, or disregarding this idea. Thanks! ^^