Alot of the time cloning of cards is the problem- but if this has happened 3 times,with different cards, it implies a few options;
1)Have you ever done a password reset/check as a result from an email from your "bank" asking you to reconfirm details? These are always scams. Or maybe you threw out bank statement with your details on. It sounds like they might have your bank details rather than just your card details which would have changed. I would ask your bank to change your bank acount details-i.e close one,and reopen with new details.
2)Or you are using your cards regularly at the same place where the problemis occuring. This could be a dodgy cash point, a shop or restaurant etc where they are swiping your card (often out of site,can you think of any non chipand pin places you go?),or if you are paying over the phone for anything for example pizza.