What you should do if your smartphone had used more than subscribed bandwidth?
Android user. Menu Settings>Wireless and Network>Mobile Networks
Disable packet data. With this, your phone will not be able to browse internet and no background process silently upload files, photo, images, email, etc..to or from the internet.
Maxi$ user will be charged maximum of RM250 if you exceed. If you had exceed, better for you to exceed a lots (2-5GB) and not only 70MB and need to pay RM250.