People seem to be missing this 'Enable SMS notifications' link at the top (which i can understand), I'm just looking for a suggestion as to how to make this more intuitive while still keeping the same layout.
This may or may not be considered "keeping the same layout" but what came to mind immediately was this: add checkboxes for SMS notifications next to each relevant entry. The space is already there.
What you have here makes it seem as if once you enable SMS notifications, you will get those notifications for all of the listed reasons. If that's not how the technical back-end works, then what I'll say here is irrelevant, but from the user's perspective, I can imagine they would want to be able to tune SMS notifications just like they can tune email notifications (the one exception being the first option, for the email digest).
Updated Based on the OP's comment that the technology doesn't support across-the board notifications, I'm adding more info below.
I would approach this in one of the following ways right now, where "now" means "the feature set isn't complete":
I would try something like the image below. It allows you to keep a similar layout, while making it very clear that there is a step required to enable text notifications.