Originally Posted by pon18n

Sometimes, some Thai company would have problems with certain credit cards online, but not on the phone. I've had an occasion where I called an airline company complaining about online transaction and they just told me that the card I was using (which I've used it to buy plenty of things on the internet) does not work with their web interface, and I could only do it by phone.

Not saying that was your case, but it's a possibility.