these scams began when large firms outsourced their call center support to India, they have become quite cleaver at what they do - it is not unusual to have someone with an Indian accent on a call center, what they do is identify known customers of paid services/online shopping etc - they accumulate this personal information either from existing call center accounts or from the companies themselves were customer data is shared by planted employees or paid for with bribes, once they have this personal data they can then target mostly vulnerable elderly people and trick them through various methods to steal from them - huge sums are involved
I remember someone asking me about the number Indian eateries around pattaya that never seem to have customers - seems they have the answer