Why won't I get twitter notifications sent to my phone?

[Megan]

I have mobile notifications turned on, and I receive tweets from some people, but for others I don't. I used to get all of the person's tweets, then I'd only get a few, and now I get no tweets at all from this person. On twitter, it still says I follow them and that I get their notifications sent to my phone..but yet I don't get them. Does anyone know why this happens and how I can fix it?
When I say notifications, I mean like text messages. I don't have a smart phone, so I get the tweets sent through texts.
Wahh >.< It's so annoyingggg. If you ever figure out how to fix it, please let me know! Thank youuuu =]

[abcd]

I am having the same problem! Is your phone an iphone? I was wondering maybe it's an iphone issue.

Edit: Oh. Yeah, I'm talking about text messages too. I don't get them even when the mobile notification is turned ON on that person.