How to block pesky SMSes
The first thing you should do is get your number registered on the DND (Do Not Disturb) list. You can start the service by sending "Start 0" to 1909 or simply by calling 1909. Note that registering your number on the list take a few days.
Alternately, if you have an Android smartphone, you can install a free app called SMS Blocker by Optinno. It is a free app with an intelligent filter that automatically detects and blocks all spam SMS. If you continue to get spam even after installing the app, you can manually add those senders to a blocked 'blacklist' .
The app maintains a log of all blocked messages and even shows a notification when something is blocked. Blocking the messages and registering with DND should solve your problem.