I've never considered trying to verify my Facebook account until I have to create app for Facebook social plugin, Recommendations Bar on Facebook Developers website. I got the prompt by CAPTCHAs spam detection while creating a new app. I entered word verification but it stops proceeding over creating new app. After several attempts, it still won't allows me to proceed except having my Facebook account verified with mobile number. In the end, it left me no choice but to add my phone number in Facebook Mobile Settings page for account verification.
In the Facebook Mobile Settings page, I've turned off text notifications, Never text me Facebook Messages, and 1 as maximum number of daily texts limit (no zero in the options, weird!). But I'm still receiving at least one Facebook alert per day and charging me daily. It is really irritating because this is not what I wanted after I have handed my trust (mobile number) to Facebook, all I want is just to get my Facebook account verified only.
I did a search on Facebook and here's the solutions how to stop/deactivate mobile texts from Facebook:
From your phone, you can simply text "Off" (without quotation marks) to your number. You will receive a text message back confirming that Facebook texts are now off.If the above doesn't help, you probably have to contact your network provider because every network provider have their own SMS keywords and shortcode. Your answer is most probably here actually.
From your computer, you can go to the Mobile tab of your Account Settings page and change your settings to "Off." Note that you can still send text messages to the same number to update your status or take actions Facebook.
You can also choose to completely remove a number from your account on this page by clicking "remove" next to the phone number that you wish to remove.
I have also googled Malaysia major mobile carriers, so here's how to stop Facebook SMS service via text:
For Celcom users,
Text STOP SMS and send to 32665
For DiGi users,
Text STOP FB and send to 2325