Has any one ever had problems withdrawing money from overseas ATM using a nat west debit card, maestro/cirrus?

While on a months holiday to visit our son in maryland usa, we were unable to withdraw any money from our account, the local banks there did everthing possible to help us, even rang the security/fraud protection in uk, but all the answer they got was that our card was invalid, and wrong pin number,so we had to use our cresit card for everything, no problem there!. We had notified the bank 1week before our departure to the states, and was told all would be fine to use the ATMs. On our arrival back in uk we went to local supermarket, to get food in ect, put our pin in , and was denied again, felt so stupid,the superviser called the nat west card protection for us , and i was asked my security password, and was told it was wrong, after 3 tries i was told to go into local branch. On arrival to local branch they contacted the security/card protection, who then informed me that i had tried 4 times to withdraw $400, from bank in maryland, and tried to purchase goods in morrisons supermarket, said they blocked our card because of irregular withdrawels, never asked for security qustion, just said it would be all cleared ready for use in 15 min, then they hung up.So now i will have to pay the high interest for using master card, which i did not want to do, as am retired and on state pension, as any one else had this kind of hassle while overseas?, thinking of changing banks, as my friends son who has gone to new zealand can not withdraw his money out and has had to use credit card.