How to deactivate unknown VAS packs on your smartphone...

Telecom operators in India are infamous for activating value-added services without the consent of the consumer. This happens mostly to prepaid subscribers. Many a times users are caught unaware as to why their prepaid account balance has automatically got deducted due to services they haven't subscribed.
Getting in touch with the customer support is mostly a waste of time. The call centre executives offer lame reasons and solution to counter the problem. They always try to make the consumer believe that it is due to some feature/service activated by them.
One of the patented reason for activating VAS without the consent of the user is- "Sir/ ma'am, this depends on your internet activity. There are some sites which you should not visit. These website are rogue and automatically deducts your balance.
As the calls to the customer care is chargeable, the executives continue with their baseless solutions and reasons. In the background, the VAS continues to consume account balance. Most of these VAS automatically gets subscribed on a montly basis if not stopped. So, in the long run, a prepaid subscriber can lose a lot of money if they are unaware.
In order to restrict telcos from forceful activation of VAS, DoT has dedicated a service to help subscribers. While the service was announced way back in 2013, very few subscribers seem to be informed about it.
All that a consumer needs to do to use this service is send an SMS by typing "STOP" to 155223. This is a toll free number. The user will get a reply from the same number informing about the list of VAS packs activated on their mobile. To deactivate these services, he just needs to reply accordingly.
It is a good practice to check VAS subscriptions every now and then to avoid unnecessary balance