I was using the following website to purchase my cards for more than 1 year and six months. I found out that they are having the worst customer service, and the worst cards, which do not provide the minutes as advertised. After getting frustrated by their service, I want to advise every body, beware of the following website to purchase your phone cards.
http://cleanasiacard.com/
Once you start using their cards, if you want to dis-continue to use their service, they are not removing your credit card service from their database. And when you request them to remove your credit card information from their database, they say that they can not do it.
So friends, the best alternative that I found is Reliance Card for the time being.