I was in Singapore using clay Singapore local sim card, which was a post paid one. Because I knew I would be using the data services more, I specially got a data pack along with the regular voice call plan. I had not even used half the capacity of the data , must be around 500MB, that I started getting messages everytime that I surfed the internet on the phone that I was being charged. And when I called the customer care, they said that its not being charged but will be discounted from the final bill. After 10 days of coming back, I got their ebill with every kb charged for surfing and using data on the phone. Not only that when I carefully checked the bill, they had doubly charged for calls also. It is such a sick thing to do, and its so frustrating fighting with these people for your own money. It was a one time mistake that I used clay sim cards, I would neither use nor recommend them to any of my friends.