There were several factors to consider on missing load it can either be Value Added Services subscription or Data Charge.
For VAS, call the hotline and request to stop all VAS subscription on your account, it would be helpful if you could provide the four digit access code that sends confirmation message to your phone.
For Data Charge you may activate SURF ALERT feature to safeguard your account from unwanted data charge,
Text SURFALERT ON to 8888 to activate.
(Browsing the internet will only be possible if there is existing Data subscription eg. Gosurf)
check the link below for procedures on how to activate this feature.