I was going to Singapore for 4 days and was strolling around the T3 airport. This matrix guy walked up and sweet-talked me into this really nice deal wherein I would have a phone number in Singapore and it would be unlimited usage at a flat rate of 500 Rs a day. I, like a fool, thought it was sweet deal and instead of being charged on my local carrier(airtel) took the matrix scheme. Four days in Singapore went off well. The phone worked fine and I used it only to check for emails. 3 weeks later I got a bill for 38, 000 Rs. As they took my credit card details at the time of getting the sim- there was nothing I could do about it.
In sum, I would strongly advice against this. Don’t believe their salesperson. Avoid this SCAM!