you will need to contact TMO either through calling in (tier 1 support), visiting a store or by contacting them through one of their social media platforms like Facebook or Twitter (tier 2 support).
if your wife is set up as the primary account holder (PAH) she will need to either be the one to contact TMO or have her add you on as a person that can make changes to the account/lines etc..
also stop posting personal info..fully public site and everyone and their mom now have your number. i went ahead and marked it to be edited out.
also if you go the FB/Twitter route make sure to send them a DM..do not post on their main page.
It could be that it's a grandfathered plan and that data option is not available anymore