Don't use Celcom! (Kuala Lumpur)
Hi after having my account charged by "third parties" and finally speaking to someone honest at Celcom customer helpline it seems 100,000's of customers are complaining about this issue.
Basically they allow random 3rd party suppliers deduct charges for "games" with no proof of authorisation or even request by the customer. So someone has sold a long list of numbers to con men who are charging 100,000's of customers 1.50 RM per day - nice little earner that one - and Celcom's official attitude is "it's your fault log a complaint and go away". It can add up if you get several a day!
So use Maxis or Digi if new. I am going to move to Maxis and give them a try to see if they are any better.