I own a MasterCard credit card. It has a 3-digit CVV code written on it, and I've always used it to make purchases.

Now I'm in Ireland and everyone here wants me to insert a 4-digit code. The problem is that I don't have such code, and looking on the web no MasterCard credit card has it. If I try to enter 3 digits and then hit "OK", nothing happens.

Another strange thing is that nobody wants me to swipe the card. They just want to use the chip.

Why and what can I do?