Matrix International Sim cards have been nothing but really helpful to me. I had bought their post paid sim card for China for almost a week. After 2 days into work I realized I would have to stay longer than a week and wasn’t sure if my contract would last me longer than a week. I called their support number and inquired if I were to use the same number more than the duration of the contract how would it be.. Very patiently Varsha explained that I could continue to use it for as long as I were in Malaysia. They would just need an email from my end and the regular plan that I was on, would apply. I was quite relieved because matrix has good network services in Guangzhou. And this made things a lot easier and simpler for me. Thanks Guys for being such a great help..