Can anyone explain the following problem? When I arrived in Nice, France, and went to pickup my rental car, the agent said my Bank One visa card came back "not valid". Tried my wife's Bank One card, still not valid. I then gave them my MBNA visa card and it processed with no problem. I called Bank One and they said their records showed no attempt to use the card. On five other occasions my Bank One visa was refused as not valid. In one instance a hotel manager entered the nos. manually, still not valid. In each case th MBNA card was accepted without problem. In a dozen other cases the Bank One visa was accepted and processed without any problems. When I returned home I called Bank One and asked why would the merchants sometimes not accept their card but always would the MBNA card. Bank One could offer no explanation. I was lucky to have taken 2 different visa cards. Does anyone have any ideas? Thanks.